Flat config is the new config system used by ESLint 9.
To make the migration easier, they also added
flat config support to ESLint 8.
This commit migrates the various ESLint configs in the repository to use
the new system, **without** upgrading to ESLint 9 yet.
This commit changes the `JpxImage.decode` method signature to define the
`ignoreColorSpace` argument as optional with a default value. Note that
we already set this default value in the `getBytes` method of the
`src/core/decode_stream.js` file since this option only seems useful for
certain special cases and therefore shouldn't be mandatory to provide.
Moreover, the JPX fuzzer is changed to use the new `JpxImage` API.
Having just tested PR 17337 locally I noticed that especially the `JpxImage`-test causes a "ridiculous" amount of warning messages to be printed, which doesn't seem helpful.
Given that only actual `Error`s should be relevant here, we can easily disable this logging during the tests.
