install: add FreeBSD's -U (unprivileged) option #5038

Job	Run time
L10n/Locale Support Verification	6m 54s
L10n/Locale Embedding - Ls Utility	1m 12s
L10n/French Integration Test	1m 53s
L10n/Clap Error Localization Test	2m 19s
L10n/Multi-call Binary Install Test (macos-latest, feat_os_macos)	4m 23s
L10n/Locale Embedding - Cat Utility	50s
L10n/Locale Embedding - Multicall Binary	2m 44s
L10n/Fluent Syntax Check	18s
L10n/Build and Test (macos-latest, feat_os_macos)	5m 42s
L10n/Multi-call Binary Install Test (ubuntu-latest, feat_os_unix)	3m 44s
L10n/Locale Embedding - Cargo Install	59s
L10n/Embedded Locale Regression Test	1m 40s
L10n/Build and Test (ubuntu-latest, feat_os_unix)	3m 36s
L10n/Installation Test (Make & Cargo) (ubuntu-latest, feat_os_unix)	6m 20s
L10n/Build and Test (windows-latest, feat_os_windows)	8m 46s
L10n/Installation Test (Make & Cargo) (macos-latest, feat_os_macos)	7m 35s
L10n/Locale Embedding Regression Test	3s
	58m 58s

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