[8.2.0] Set macro symbol's exported location as MacroFunction's callable location for Starlark stack (#25802)

This ensures Starlark instantiation stack for rule targets defined in a
symbolic macro shows both the macro's location and symbol.

Requires changing StarlarkThread to track the location of where symbols
are exported.

As follow-up, we should do the same for rules, providers, and aspects.

PiperOrigin-RevId: 745731053
Change-Id: I6732a9762fbc932d823a70d7753a2b6edc140df6

Commit

https://github.com/bazelbuild/bazel/commit/a3e26ed827badf6c4cf4f09aa37747622357635c