assistant2: Add keybinding to toggle `ContextPicker` #37703

Job	Run time
Check formatting and spelling	27s
Check Postgres and Protobuf migrations, mergability	11s
(Linux) Run Clippy and tests	16m 35s
(macOS) Run Clippy and tests	8m 25s
(Linux) Build Remote Server	1m 32s
(Windows) Run Clippy and tests	15m 17s
Create a macOS bundle	0s
Create arm64 Linux bundle	0s
Create a Linux bundle	0s
Auto release preview	0s
	42m 27s

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