FindMatlab: Restore support for finding Matlab without any languages

Revise commit 657064b6d4 (FindMatlab: Refactor: Eliminate
_matlab_64Build, 2024-01-24, v3.30.0-rc1~594^2~5) to more faithfully
reproduce the original behavior.

Revise commit 91c672e5ae (FindMatlab: Use find_package(Threads) instead
of checking -pthread, 2024-02-02, v3.30.0-rc1~594^2~1) to restore the
old behavior of looking for threads only with C or CXX enabled.

Fixes: #26121