[NFC][clangd] fix clang-tidy finding on isa_and_nonnull

This is a cleanup of the only llvm-prefer-isa-or-dyn-cast-in-conditionals finding in the clangd code base. This patch was created by automatically applying the fixes from clang-tidy.

Differential Revision: https://reviews.llvm.org/D113899

GitOrigin-RevId: 7aa2ce0fab3c21cf87c5884f6bf8bdece1b6fe1c
1 file changed