ci: set GOTOOLCHAIN=local for unit tests #2899

Job	Run time
Smoke Tests	0s
Prepare Go modules cache	10s
macos-latest (AppSec disabled)	2m 2s
windows-latest (AppSec disabled)	2m 52s
linux/amd64 golang:1.22-bookworm	1m 28s
ubuntu-latest-16-cores (AppSec disabled)	1m 7s
linux/arm64 golang:1.22-bookworm	2m 43s
linux/amd64 golang:1.22-bullseye	1m 21s
linux/arm64 golang:1.22-bullseye	2m 29s
macos-12 go1.22	6m 20s
linux/amd64 golang:1.22-alpine	1m 13s
macos-12 go1.21	5m 42s
linux/arm64 golang:1.22-alpine	2m 40s
macos-14 go1.22	3m 32s
linux/amd64 golang:1.21-bookworm	1m 24s
macos-14 go1.21	3m 41s
linux/arm64 golang:1.21-bookworm	2m 56s
linux/amd64 golang:1.21-bullseye	1m 29s
linux/arm64 golang:1.21-bullseye	2m 58s
linux/amd64 golang:1.21-alpine	1m 21s
linux/arm64 golang:1.21-alpine	2m 34s
	50m 2s

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