When an MR diff is "Too Large", highlight it like other collapsed diffs

What does this MR do?

For #257895 (closed)

Changes the rendered error when a file is marked as too_large by the back end to look like our other errors.

How

The previous version simply rendered the error return by the BE into a <div>.
The new version identifies the type of error and renders a separate UI.

NB: The old "dump-the-backend-error-html-into-a-div" is still present, but may(?) never appear since the only error I've ever seen is the special-case "too_large" which we're explicitly handling.

Screenshots (strongly suggested)

	Before	After
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Interactivity

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• [-] Separation of EE specific content

Availability 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
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done

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