Autosize editor after indent/newline

Why was this closed?

Because other regressions still persisted in these recent changes, we've opted to revert and iterate instead of merging this fix. Here's the revert MR https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/31391

What does this MR do?

Fixes #65432 (closed).

Auto-sizes the Markdown editor after performing an unindent, indent, or newline. These events have a custom handler, so the autosize handler doesn't pick up on them anymore.

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry for user-facing changes, or community contribution. Check the link for other scenarios.
• [-] Documentation created/updated or follow-up review issue created
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• Separation of EE specific content

Performance and testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team