Add/update plugins examples

[byrnHDF]

fixes #5669

---

Important

Add Granular BitRound filter plugin example and update CMake and test configurations.

• New Plugin Example:
  • Adds h5ex_d_granularbr.c to demonstrate Granular BitRound filter usage.
  • Updates CMakeLists.txt to include ENABLE_BITROUND option and add h5ex_d_granularbr to dyn_examples.
• Testing:
  • Adds h5ex_d_granularbr.tst and h5ex_d_granularbr.ddl for testing the Granular BitRound filter.
  • Updates HDF5PluginCache.cmake to set ENABLE_BITROUND to OFF when H5PL_ALLOW_EXTERNAL_SUPPORT is GIT.
• Misc:
  • Fixes whitespace in h5ex_d_bitgroom.tst.

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[ellipsis-dev]

Typographical error in the printf string: use "\n" instead of "/n". Change printf("/nFAILED to close library/n") to printf("\nFAILED to close library\n").

Suggested change

	printf("/nFAILED to close library/n");
	printf("\nFAILED to close library\n");

[byrnHDF]

Fixed all instances.