[dlib] Fix dependencies

[dg0yt]

Alternative to #50979.

• Put find_dependency before actual imported targets. Fixes [dlib] dlibConfig.cmake fails with "LAPACK::LAPACK target not found" — find_dependency calls placed after targets include #50976.
• Cleanup.

[dg0yt]

Key change: Call find_dependency() early.

[Neumann-A]

Put find_dependency before actual imported targets.

My last information was that CMake does not care about order as long as the target exists at the end of of configure (and there is no if(TARGET) check observing the target early).

[dg0yt]

My last information was that CMake does not care about order as long as the target exists at the end of of configure (and there is no if(TARGET) check observing the target early).

It is right that typical errors are thrown only in the generation step, after the configuration step.

OTOH proper operation of config mode with imported targets and useful diagnostics relies on find_dependency being early in the config file. Get the config file right before tracing errors because this is something which can be done.