Test: Command Palette improvements

[bpasero]

• win - @ramya-rao-a
• mac - @aefernandes
• linux - @joaomoreno

Complexity: 2
Refs: #13080 and #17163

The command palette got some new features and UX updates.

UX

• verify you see keybindings now represented in the same way as they show up in the keybindings editor

Preserve Input

• verify a new setting workbench.commandPalette.preserveInput can be used to let it restore the previous typed input when opened (only when you open via the workbench.action.showCommands command, which is Ctrl/Cmd+Shift+P)
• this input will be reset once you restart (e.g. not persisted)
• verify you see the entire input value being selected so that typing just removes it (except for the leading ">")

MRU
We now show the most recently used commands on top of the other commands (similar to how we show most recently opened files in the files picker)

• verify that the most recently used command always shows to the top
• verify that when you start typing you see the MRU list as well as the other commands sorted and the most recently used commands always stay at the top
• verify you are not seeing the same command in the MRU list and the other category
• verify the number of entries is limited via the setting workbench.commandPalette.history
• verify that you can disable this feature via setting workbench.commandPalette.history: 0

[roblourens]

@aefernandes when you're done with a test item, you can unassign yourself and close the issue (if you're the last one), thanks!