10.x: reject a string set compared with a value under a collation that may not compare bytes (port of #507) #512

Problem

On main, the PR for #507 makes a query throw when it compares a string set with a value under a collation that may not compare bytes. On release/10.x, Members.Contains(g.Owner) with a case-insensitive Owner matches {A} for "a", and ExecuteUpdate with Remove(g.Owner) deletes A. #496's 10.4.0 row says that class is fixed.

Change

Cherry-pick the #507 PR's commits with -x into a PR against release/10.x: the guard's collation derivation, the convention's annotation, the tests (with the compiled-model helper), the oracle, both seeds and claim E89.

• 10.x specifics: the changelog row goes under ### Changed answers in [10.4.0] (root and EF Core), linking this issue and #changed-answers-in-1040. The value-side half goes into Check string set columns with a collation under ## Changed answers in 10.4.0. Stacked on YearMonthRange Clamp and UpperBound() in a filter compare as the month's last day, so == against the month is false #506's port, because both edit those sections.

Done when

On release/10.x, the tests pass on the EF Core 10.0.0 floor and on CI's newest-patch leg, they fail with the fix reverted, and both seeds are caught.

Release

### Changed answers in 10.4.0. Fixed only on release/10.x, so close it by hand.