Enable WHERE name optimization for all queries, remove feature flag

[ukutaht]

Follow-up to #6145

Confirmed the optimization is working in production with spot checks.

[ukutaht]

Results from one test. visit:source breakdown with event:props filter from a large client. Two identical queries with the only difference being the presence of WHERE name != 'engagement' filter:

before: 65.25 GiB read bytes, query duration 3,423ms (SelectedMarks':10936, 'FunctionExecute':144,842)
after: 35.20 GiB read bytes, query duration 1,383ms ('SelectedMarks':5919, 'FunctionExecute':84,162)

This optimization will only affect larger sites (due to granule size, smaller sites will not have sufficient clustering in storage) but the improvements should be pretty broad across many queries that scan the events table.

[aerosol]

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