experiment(derived data): Add decorator for merged groups

[ceorourke]

Add a decorator to indicate that we want to have different behavior for merged groups - in some cases we want the default behavior (use whatever is most recent) and in some cases we may want to prioritize the non-merged group's log over the merged in ones. This tries out a way of accomplishing that for the case where each group is assigned to a different user/team and the case where each group has set a different priority.

[ceorourke]

add to this for whichever other ones will share this behavior

[github-actions]

Backend Test Failures

Failures on 4dc8639 in this run:

tests/sentry/issues/derived/test_aggregators.py::test_merged_assign_advances_progress — log

[gw0] linux -- Python 3.13.1 /home/runner/work/sentry/sentry/.venv/bin/python3
tests/sentry/issues/derived/test_aggregators.py:574: in test_merged_assign_advances_progress
    _run_for_feature(
tests/sentry/issues/derived/test_aggregators.py:50: in _run_for_feature
    return p.run(entries)[feature]
           ^^^^^^^^^^^^^^
src/sentry/issues/derived/framework.py:309: in run
    state = self.step(state, entry)
            ^^^^^^^^^^^^^^^^^^^^^^^
src/sentry/issues/derived/framework.py:288: in step
    result = agg.fn(subset, entry)
             ^^^^^^^^^^^^^^^^^^^^^
src/sentry/issues/derived/merge.py:54: in wrapper
    return merged_fn(state, entry)
           ^^^^^^^^^^^^^^^^^^^^^^^
src/sentry/issues/derived/aggregators.py:140: in _track_progress_merged
    if entry.type in (GroupActionType.ASSIGN):
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
E   TypeError: argument of type 'GroupActionType' is not iterable

tests/sentry/issues/derived/test_aggregators.py::test_merged_set_priority_does_not_advance_progress — log

[gw0] linux -- Python 3.13.1 /home/runner/work/sentry/sentry/.venv/bin/python3
tests/sentry/issues/derived/test_aggregators.py:590: in test_merged_set_priority_does_not_advance_progress
    _run_for_feature(
tests/sentry/issues/derived/test_aggregators.py:50: in _run_for_feature
    return p.run(entries)[feature]
           ^^^^^^^^^^^^^^
src/sentry/issues/derived/framework.py:309: in run
    state = self.step(state, entry)
            ^^^^^^^^^^^^^^^^^^^^^^^
src/sentry/issues/derived/framework.py:288: in step
    result = agg.fn(subset, entry)
             ^^^^^^^^^^^^^^^^^^^^^
src/sentry/issues/derived/merge.py:54: in wrapper
    return merged_fn(state, entry)
           ^^^^^^^^^^^^^^^^^^^^^^^
src/sentry/issues/derived/aggregators.py:140: in _track_progress_merged
    if entry.type in (GroupActionType.ASSIGN):
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
E   TypeError: argument of type 'GroupActionType' is not iterable

tests/sentry/issues/derived/test_aggregators.py::test_merged_set_priority_does_not_override_native — log

[gw0] linux -- Python 3.13.1 /home/runner/work/sentry/sentry/.venv/bin/python3
tests/sentry/issues/derived/test_aggregators.py:606: in test_merged_set_priority_does_not_override_native
    _run_for_feature(
tests/sentry/issues/derived/test_aggregators.py:50: in _run_for_feature
    return p.run(entries)[feature]
           ^^^^^^^^^^^^^^
src/sentry/issues/derived/framework.py:309: in run
    state = self.step(state, entry)
            ^^^^^^^^^^^^^^^^^^^^^^^
src/sentry/issues/derived/framework.py:288: in step
    result = agg.fn(subset, entry)
             ^^^^^^^^^^^^^^^^^^^^^
src/sentry/issues/derived/merge.py:54: in wrapper
    return merged_fn(state, entry)
           ^^^^^^^^^^^^^^^^^^^^^^^
src/sentry/issues/derived/aggregators.py:140: in _track_progress_merged
    if entry.type in (GroupActionType.ASSIGN):
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
E   TypeError: argument of type 'GroupActionType' is not iterable

tests/sentry/issues/derived/test_aggregators.py::test_merged_root_cause_does_not_advance_progress — log

[gw0] linux -- Python 3.13.1 /home/runner/work/sentry/sentry/.venv/bin/python3
tests/sentry/issues/derived/test_aggregators.py:622: in test_merged_root_cause_does_not_advance_progress
    _run_for_feature(
tests/sentry/issues/derived/test_aggregators.py:50: in _run_for_feature
    return p.run(entries)[feature]
           ^^^^^^^^^^^^^^
src/sentry/issues/derived/framework.py:309: in run
    state = self.step(state, entry)
            ^^^^^^^^^^^^^^^^^^^^^^^
src/sentry/issues/derived/framework.py:288: in step
    result = agg.fn(subset, entry)
             ^^^^^^^^^^^^^^^^^^^^^
src/sentry/issues/derived/merge.py:54: in wrapper
    return merged_fn(state, entry)
           ^^^^^^^^^^^^^^^^^^^^^^^
src/sentry/issues/derived/aggregators.py:140: in _track_progress_merged
    if entry.type in (GroupActionType.ASSIGN):
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
E   TypeError: argument of type 'GroupActionType' is not iterable