fix(replays): Guard against IndexError in query processing with leading logical operators

[sentry]

This PR addresses an IndexError: list index out of range occurring in src/sentry/replays/usecases/query/__init__.py within the attempt_compressed_condition function.

The root cause was that attempt_compressed_condition would unconditionally access result[-1] without checking if result was empty. This became an issue when handle_search_filters processed search_filters lists that began with a logical operator like 'AND' or 'OR'. In such cases, the look_back variable would be set, leading to a call to attempt_compressed_condition while the result list was still empty, thus triggering the IndexError.

The fix introduces a guard at the beginning of attempt_compressed_condition: if result is empty, the condition is simply appended, and the function returns. This prevents the IndexError by ensuring result[-1] is only accessed when result is guaranteed to contain at least one element, preserving the existing compression logic for valid scenarios.

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Fixes SENTRY-5NH5