Add dialect to ft aggregate

[DvirDukhan]

Pull Request check-list

Please make sure to review and check all of these items:

• Does $ tox pass with this change (including linting)?
• Do the CI tests pass with this change (enable it first in your forked repo and wait for the github action build to finish)?
• Is the new or changed code fully tested?
• Is a documentation update included (if this change modifies existing APIs, or introduces new ones)?
• Is there an example added to the examples folder (if applicable)?
• Was the change added to CHANGES file?

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Description of change

Added dialect option to aggregate command

[codecov-commenter]

Codecov Report

Base: 92.23% // Head: 92.22% // Decreases project coverage by -0.01% ⚠️

Coverage data is based on head (0c782d4) compared to base (f10c81a).
Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

@@ Coverage Diff @@ ## master #2537 +/- ## ========================================== - Coverage 92.23% 92.22% -0.02%  ========================================== Files 113 113 Lines 29380 29388 +8 ========================================== + Hits 27098 27102 +4  - Misses 2282 2286 +4 

Impacted Files	Coverage Δ
redis/commands/search/aggregation.py	79.72% <100.00%> (+0.85%)	⬆️
tests/test_asyncio/test_search.py	98.63% <100.00%> (+<0.01%)	⬆️
tests/test_search.py	99.16% <100.00%> (+<0.01%)	⬆️
tests/test_cluster.py	96.79% <0.00%> (-0.34%)	⬇️
tests/conftest.py	85.71% <0.00%> (+0.77%)	⬆️

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