[Do not merge] Specify `Accept` header for `toolcache.downloadTool` #7761

Job	Run time
Packaging: Config and input (macos-latest, linked)	1m 19s
Packaging: Config and input (ubuntu-latest, default)	1m 29s
Packaging: Config and input (windows-latest, default)	6m 14s
Packaging: Config and input (macos-latest, default)	1m 51s
Packaging: Config and input (ubuntu-latest, nightly-latest)	1m 26s
Packaging: Config and input (ubuntu-latest, linked)	2m 0s
Packaging: Config and input (windows-latest, nightly-latest)	3m 53s
Packaging: Config and input (macos-latest, nightly-latest)	2m 0s
Packaging: Config and input (windows-latest, linked)	4m 12s
	24m 24s

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