Disable clang-tidy action in favor of clangd-tidy (#6037)

Generally seems to be working as intended: clang-tidy has variance from
a few minutes to an hour; clang-tidy hovers around 10 minutes. In this
case, the long tail of slow execution is more visible, partly because
tests will often take close to 10 minutes, if not more.

Branch enforcement should already be switched.

Author: jonmeow