MacOS Unit Test failures/errors on GitHub Action Runners

[v1v]

MacOS 13 test failures

See: https://github.com/elastic/elastic-agent/actions/runs/15766619034/job/44444209135?pr=8596#step:4:1065

=== Failed
=== FAIL: pkg/testing/tools/git TestGetReleaseBranches (0.06s)
    git_test.go:22: []
    git_test.go:23: 
        	Error Trace:	/Users/runner/work/elastic-agent/elastic-agent/pkg/testing/tools/git/git_test.go:23
        	Error:      	Should NOT be empty, but was []
        	Test:       	TestGetReleaseBranches

DONE 2791 tests, 14 skipped, 1 failure in 636.965s

MacOS 15 test failures

See https://github.com/elastic/elastic-agent/actions/runs/15766619034/job/44444209125?pr=8596#step:4:1063

=== Failed
=== FAIL: pkg/testing/tools/git TestGetReleaseBranches (0.06s)
    git_test.go:22: []
    git_test.go:23: 
        	Error Trace:	/Users/runner/work/elastic-agent/elastic-agent/pkg/testing/tools/git/git_test.go:23
        	Error:      	Should NOT be empty, but was []
        	Test:       	TestGetReleaseBranches

DONE 2791 tests, 14 skipped, 1 failure in 636.965s

MacOS 14 ARM test errors

See https://github.com/elastic/elastic-agent/actions/runs/15766619034/job/44444209123?pr=8596#step:4:1378

clang: error: linker command failed with exit code 1 (use -v to see invocation)

# github.com/elastic/elastic-agent/internal/pkg/agent/application.test
ld: warning: '/private/var/folders/y6/nj790rtn62lfktb1sh__79hc0000gn/T/go-link-2462[732](https://github.com/elastic/elastic-agent/actions/runs/15766619034/job/44444209123?pr=8596#step:4:733)55/000089.o' has malformed LC_DYSYMTAB, expected 98 undefined symbols to start at index 1626, found 95 undefined symbols starting at index 1626
FAIL	github.com/elastic/elastic-agent/internal/pkg/agent/application/actions/handlers [build failed]
?   	github.com/elastic/elastic-agent/internal/pkg/agent/application/actions	[no test files]
ok  	github.com/elastic/elastic-agent/internal/pkg/agent/application	3.635s	coverage: 54.5% of statements