Update Image Compression Control sample tutorial

[JoseEmilio-ARM]

Description

Documentation change only

When querying for image compression support, VK_IMAGE_COMPRESSION_FIXED_RATE_DEFAULT_EXT should be used, as shown in the extension proposal, otherwise the returned imageCompressionFixedRateFlags might be 0.

This is correct in the framework/sample, but was copied incorrectly in the tutorial.

General Checklist:

Please ensure the following points are checked:

• [x] My code follows the coding style
• [x] I have reviewed file licenses
• [x] I have commented any added functions (in line with Doxygen)
• [x] I have commented any code that could be hard to understand
• [x] My changes do not add any new compiler warnings
• [x] My changes do not add any new validation layer errors or warnings
• [x] I have used existing framework/helper functions where possible
• [x] My changes do not add any regressions
• [x] I have tested every sample to ensure everything runs correctly

• [x] This PR describes the scope and expected impact of the changes I am making

  Note: The Samples CI runs a number of checks including:

  • [x] I have updated the header Copyright to reflect the current year (CI build will fail if Copyright is out of date)
  • [x] My changes build on Windows, Linux, macOS and Android. Otherwise I have documented any exceptions

  If this PR contains framework changes:

  • [n/a] I did a full batch run using the batch command line argument to make sure all samples still work properly

[marty-johnson59]

Low risk change - merging on 2 approvals