SF: Clean up warnings around AidlComposer.{h,cpp}

This CL was uploaded with some corresponding fixes affecting the
ComposerCommandBuffer.h headers in hardware/interfaces. The pragmas to
disable specific warnings when including those files are no longer
needed, as those headers have been fixed.

There were some warnings about using calling functions marked
deprecated. For those I disabled the deprecation warning for the call,
since SurfaceFlinger still needs to make the legacy call if that's what
the vendor implementation supports.

clangd also reported three unused "using ..." directives at the top of
the file. I went ahead and remove these.

Flag: EXEMPT build and lint warnings only
Bug: None
Test: Builds

Change-Id: I160785bc44850ba8b202ed6874e1530d1fbe13e1