Allow onValueChange and onSelectionChange to trigger on the same frame, fixing a few bugs where one was not being called

[nabbydude]

Description
onValueChange and onSelectionChange have been treated as mutually exclusive, which is not the case, both can happen in a single frame. This changes withReact's onContextChange to account for that.

Issue
Fixes #5814, should fix #5910 (i do not have a mac to test with though)
Also an alternative fix for #5955, eliminating the need for the workaround in #5957, so this PR removes it.

Context
Sometimes, either from complex commands or certain browser behavior, multiple operations will happen in one frame before onChange gets called. Sometimes this can be a mix of selection and non-selection operations.
For some reason onChange gets called with an operation parameter, but this is only ever the first operation done in a frame and lacks context of a whole frame. The editor already has an operations member as a list of the operations performed in a frame, so we can just use that.

As written onSelectionChange will ALWAYS run before onValueChange, no matter which is first in the operations list. This can be changed, but this seemed like the simplest way to do it.

Checks

• The new code matches the existing patterns and styles.
• The tests pass with yarn test.
• The linter passes with yarn lint. (Fix errors with yarn fix.)
• The relevant examples still work. (Run examples with yarn start.)
• You've added a changeset if changing functionality. (Add one with yarn changeset add.)

[changeset-bot]

🦋 Changeset detected

Latest commit: 084986e

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
slate-react	Patch

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[dylans]

The change looks reasonable, but it does appear to have a few failing tests. I've not looked to see if they were already failing, if this change causes them to fail, or if the tests need to be fixed and were passing by coincidence previously.

I believe it is the result of the fix in #5976 so once that lands I'll let the tests re-run.