Provide a unified (lsp-interface INTERFACE ...) pcase form #5386

Job	Run time
test (ubuntu-latest, 27.2, false)	2m 3s
test (ubuntu-latest, 28.2, false)	2m 32s
test (ubuntu-latest, 29.4, false)	2m 33s
test (macos-latest, 28.2, false)	3m 56s
test (macos-latest, 29.4, false)	4m 15s
test (windows-latest, 27.2, false)	3m 30s
test (windows-latest, 28.2, false)	3m 23s
test (windows-latest, 29.4, false)	3m 4s
test (ubuntu-latest, snapshot, true)	1m 25s
test (macos-latest, snapshot, true)	3m 31s
test (windows-latest, snapshot, true)	4m 59s
	35m 11s

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