Setting of the `crossorigin` attribute is not necessary for same-origin images, and causes an immediate image reload (albeit from cache) necessitating the use of a load event listener which subsequently mutates the snapshot. This change allows us to avoid the mutation of the snapshot for the same-origin case.
* Modify inlineImages test to remove delay and show that we can inline images without mutation
* Add an explicit test for when the `image.crossOrigin = 'anonymous';` method is necessary. Uses a combination of about:blank and our test server to simulate a cross-origin context
* Other test changes: there were some spurious rrweb mutations being generated by the addition of the crossorigin attribute that are now elimnated from the rrweb/__snapshots__/integration.test.ts.snap after this PR - this is good
