Since the name of the menu command changes, I can only come up with one idea to create a shortcut for that command. I used UI Scripting to click on that menu item, and used an Automator Service to call the AppleScript app from a shortcut.
Using Script Editor, create a new script with this code:
tell application "System Events"
tell process "Mail"
set MoveToAgainMenu to every menu item of menu "Message" of menu bar 1 whose name starts with "Move to" and name ends with "Again"
click (item 1 of MoveToAgainMenu)
end tell
end tell
Save the script as an Application with any name you wish to use (I used "Move Again")
I saved mine in my user/Library/Application Scripts/com.apple.mail folder.
Create a new Automator Service that receives no input from application Mail
Drag in a "Run applescript" action from the Utilities Library.
Set the code in that AppleScript to:
on run {input, parameters}
tell application "Move Again" to run
end run
Save that with any name you want, including the same as your AppleScript.
Open Keyboard System Preferences, select Shortcuts tab
Select Services from the list on the left.
Find your Service name in the list and add the shortcut you want. I think cmd-opt-T hides and shows the favorites bar.
Open Security & Privacy System Preferences.
Select Privacy Tab.
Select Accessibility
Find where you saved your AppleScript app and drag it into the Allow list.
When you first run the script, it will ask to find the App you created ("Move Again" in my case).
Click the Browse button and find the app your created. That lets the AppleScript know what app to run. It will remember after the first time.
