Update dialog headers to h2 instead of h4

[adamint]

Description

PaneHeader seems like an appropriate typography for dialog headers, but it renders as an h4, which is too high of a heading number for the importance of the content. h2 is the appropriate level. No change in appearance

Before:

After:

Related: #10450

Checklist

• Is this feature complete?
  • Yes. Ready to ship.
  • No. Follow-up changes expected.
• Are you including unit tests for the changes and scenario tests if relevant?
  • Yes
  • No
• Did you add public API?
  • Yes
    • If yes, did you have an API Review for it?
      • Yes
      • No
    • Did you add <remarks /> and <code /> elements on your triple slash comments?
      • Yes
      • No
  • No
• Does the change make any security assumptions or guarantees?
  • Yes
    • If yes, have you done a threat model and had a security review?
      • Yes
      • No
  • No
• Does the change require an update in our Aspire docs?
  • Yes
    • Link to aspire-docs issue (consider using one of the following templates):
      • New (or update) doc-idea template
      • New breaking-change template
      • New diagnostic template
  • No

[Copilot]

Pull Request Overview

This PR updates dialog headers in the Aspire Dashboard to use more semantically appropriate heading levels by changing from Typography.PaneHeader (which renders as h4) to Typography.H2 for dialog titles.

• Changes dialog headers from h4 to h2 heading level for better semantic hierarchy
• Affects two dialog components that display titles to users

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
TextVisualizerDialog.razor	Updates dialog title typography from PaneHeader to H2
InteractionsInputDialog.razor	Updates dialog title typography from PaneHeader to H2

[JamesNK]

This PR changes the dialogs where we customize the header. What about dialogs that use the built in header template? They'll still be <h4>

[adamint]

This PR changes the dialogs where we customize the header. What about dialogs that use the built in header template? They'll still be <h4>

That will require changes in fluentui-blazor that I have to discuss with them about. This is a good start. The only urgent change we need is the ai assistant chat, but since we define custom headers in these two dialogs, we should also change their heading level.

[JamesNK]

Actually, I think there could be a better fix for this. We could update markdown rendering so it doesn't output h2: xoofx/markdig#368

[mitchdenny]

[JamesNK]

Prefer that we adjust markdown

#11321

[adamint]

Prefer that we adjust markdown

#11321

We need to change the header levels. h4 is not appropriate for a modal title and is misleading. The markdown is not the issue! 😄

[JamesNK]

The current typo value is Typography.PaneHeader. If FluentUI changes that type to resolve to an h2 then we don't need to make this change.