[clang-tidy] Exclude template instantiations in modernize-use-override

Added IgnoreTemplateInstantiations option to modernize-use-override
check. Allows to ignore virtual function overrides that are part of
template instantiations. This can be useful in cases where the use
of the "override" keyword is not appropriate or causes issues with
template specialization.

Fixes #38276.

Reviewed By: carlosgalvezp

Differential Revision: https://reviews.llvm.org/D147924