feat(storage): multi bucket download file api #3902

Job	Run time
test / test-dart-vm (3.3.0)	5m 0s
test / test-dart-vm (stable)	4m 52s
ddc_test / test-dart-ddc (3.3.0, chrome)	3m 45s
dart2js_test / test-dart-2js (3.3.0, chrome)	4m 0s
ddc_test / test-dart-ddc (3.3.0, firefox)	4m 8s
dart2js_test / test-dart-2js (3.3.0, firefox)	4m 12s
ddc_test / test-dart-ddc (stable, chrome)	3m 43s
dart2js_test / test-dart-2js (stable, chrome)	4m 5s
native_test / test-dart-native (macos-14)	3m 33s
ddc_test / test-dart-ddc (stable, firefox)	3m 41s
dart2js_test / test-dart-2js (stable, firefox)	4m 15s
native_test / test-dart-native (windows-latest)	3m 31s
	48m 45s

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