[CLEANUP beta] Remove Ember.Component.reopen

[SergeAstapov]

Part of #19617

[SergeAstapov]

There is related #19664 for the same removal but in built-in components

[SergeAstapov]

@mixonic looks like it's done as part of #19806 - would you like to have a small targeted PR or it does not make sense?

[mixonic]

@SergeAstapov we would like it to be one big PR, I think. This is because the removed components and much of their capability (like reopen) should all be contained within emberjs/ember-legacy-built-in-components#1. Component.reopen itself should be removed and I think will not be in emberjs/ember-legacy-built-in-components#1, but regardless I think the codepaths are likely tangled enough we should do it in a single go.

I'll review this PR to make sure I'm pulling these same things out in #19806.

Thank you for this work though, it will be a helpful reference and good gut check.

[SergeAstapov]

@mixonic thank you for explanation! Feel free to close this PR once it's not needed (I wasn't sure was doing all things right way anyways, at least CI was happy)