Introduce dropdown to allow switching between different wikidiff formats in the `Review your changes modal`. The options should be "Two Columns" and "Inline" if Wikidiff2 is installed. The Wikitext format in core renders a two-column layout by default.
== Feature Summary ==
On the current experience, a user is able to use different `diff` formats.
Introduce a dropdown to the UI so that users can easily switch between the different available formats.
== Use Cases ==
As a viewer, I am able to switch between different diff formats when review my changes.
The drop down should display the options according to installation.
Fresh install:
Do not show anything
Fresh install with Wikidiff2 enabled options:
"Two Columns", "Inline"
| Widiff2 installed|Options|
|No|No dropdown|
|Yes|'Inline', 'Two Columns'|
== Release plan ==
[] Engineering reviews and creates patch demo
[] QA review patch demo
[] Product tested patch demo
[] Merge - train will pick up change [date TBD]