[Sema] Fix variable invalid optional chaining in if context diagnostic

[LucianoPAlmeida]

In constraint generation a RemoveUnwrap is recorded when adding OptionalObject for BindOptionalExpr but when adding contextual constraint and attempting to add the contextual conversion constraint we end up in attempting repairViaOptionalUnwrap which succeed because there is a RemoveUnwrap already but returns false because the fix was recorded on a previous constraint and is not on conversionsAndFixes list. This leaves the conversion constraint as failedConstraint and solver stops without being able to form a solution and produce diagnostic.
The fix is simply assume that if repairViaOptionalUnwrap is successful we assume fixed in repairFailure already because it either record a fix or bail because there is a fix already.

Resolves #63796

[LucianoPAlmeida]

@swift-ci Please smoke test

[LucianoPAlmeida]

@swift-ci Please smoke test MacOS Platform

[xedin]

Oops, thank you!