RFR: 8373091: Make Metal the default JavaFX rendering pipeline for macOS

[Ambarish Rapte]

The metal rendering pipeline was integrated in PR #1824, It has been well tested and ready for to be default pipeline on MacOS. 
During JavaFX 26 it was temporarily set as default for 6 weeks, during which we did not see any issues.
Changing the pipeline to default early in jfx27 would offer more testing.

If required one can always use es2 pipeline by passing `-Dprism.order=es2`

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Commit messages:
 - default pipeline mtl

Changes: https://git.openjdk.org/jfx/pull/2050/files
  Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=2050&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8373091
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jfx/pull/2050.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/2050/head:pull/2050

PR: https://git.openjdk.org/jfx/pull/2050