Implement dropdown menu for choosing a default terminal application from inside the Windows Terminal Settings UI
## PR Checklist
* [x] Closes#9463
* [x] I work here.
* [x] Manual tests passed
* [x] https://github.com/MicrosoftDocs/terminal/issues/314 (and cross reference #9462)
## Detailed Description of the Pull Request / Additional comments
- Adds dropdown menu and a template card for displaying the available default applications (using the same lookup code as the console property sheet `console.dll`)
- Adds model to TSM for adapting the data for display and binding on XAML
- Lookup occurs on every page reload. Persistence only happens on Save Changes.
- Manifest changed for Terminal to add capability to opt-out of registry redirection so we can edit this setting
## Validation Steps Performed
- [x] Flipped the menu and pressed Save Changes and launched cmd from run box... it moved between the two.
- [x] Flipped system theme from light to dark and ensured secondary color looked good
- [x] Flipped the status with a different mechanism (conhost propsheet) and then reopened settings page and confirmed it loaded the updated status
[Git2Git] Merged PR 5760120: Add propsheet chooser to Windows
Now the inbox console propsheet can choose which terminal is default
Related work items: MSFT-32007202 #492
Retrieved from https://microsoft.visualstudio.com os.2020 OS official/rs_wdx_dxp_windev d80f506858bd990c267de6cefae7ff55707b3a57
Contains:
- Delegation Configurator that can lookup/edit/save configuration information to registry
- Conhost can lookup the CLSID of a registered default
- Conhost has the ability to handoff a starting visible-window interactive session to the registered default
- Velocity key since this is a big deal and we want to be careful
- IDL for the interface
Related work items: MSFT-16458099
Retrieved from https://microsoft.visualstudio.com os.2020 OS official/rs_wdx_dxp_windev 0ca55027d8180fbbaa145f2fe7a15005856c0f7c
