gpui: Rename `GPUSpecs` to `GpuSpecs` #37782

Job	Run time
Check formatting and spelling	31s
(macOS) Run Clippy and tests	8m 31s
(Linux) Run Clippy and tests	12m 9s
Check Postgres and Protobuf migrations, mergability	13s
(Linux) Build Remote Server	1m 51s
(Windows) Run Clippy and tests	14m 16s
Create a macOS bundle	0s
Create arm64 Linux bundle	0s
Create a Linux bundle	0s
Auto release preview	0s
	37m 31s

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