[clang-tidy] Exclude class/struct scope variables from...

[clang-tidy] Exclude class/struct scope variables from cppcoreguidelines-avoid-non-const-global-variables

Ignore static variables declared within the scope of class/struct.
Those variables should be covered by I.3 rule.

Fixes: #47384

Reviewed By: carlosgalvezp

Differential Revision: https://reviews.llvm.org/D157180