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.
