[Terminal]: 'Save' and 'Discard Changes' button should remain in disabled state until we don't make any changes inside Settings page.

### Windows Terminal version

1.13.10336.0

### Windows build number

10.0.22543.1000

### Other Software

**Test Environment:**
OS: Windows 11 Version Dev (OS Build 22543.1000)
App: Windows Terminal Preview
Screen Reader: Narrator

### Steps to reproduce

**Repro Steps:**
1. Open Windows Terminal.
2. Open Settings page using 'Ctr+,'.
3. Observe the issue.

**User Experience:**
Users UX will not be good especially Screen Reader as nothing will happen when they activate 'Save' and 'Discard' as result they will not be able to figure out whether these buttons are actionable or not.

**Attachments:**
['Save' and 'Discard Changes' button should remain in disabled state until we don't make any changes..zip](https://github.com/microsoft/terminal/files/8021036/Save.and.Discard.Changes.button.should.remain.in.disabled.state.until.we.don.t.make.any.changes.zip)

### Expected Behavior

'Save' and 'Discard Changes' button should remain in disabled state until we don't make any changes inside Setting page.

### Actual Behavior

'Save' and 'Discard Changes' buttons are in active state even if they are not actionable inside Setting page.

Start by reproducing the behavior in the Windows Terminal Settings page on Windows 11, using the stated version and Narrator. Verify that Save and Discard Changes are disabled on initial entry, become actionable after a settings change, and remain understandable to screen-reader users.

Written by the indexing model from the issue text.