feat: Update STS web identity credentials provider & add integration test #2824

Job	Run time
apple (macos-13-xlarge, Xcode_14.1, platform=iOS Simulator,OS=16.1,name=iPhone 14)	5m 58s
linux (focal, 5.7)	6m 31s
apple (macos-13-xlarge, Xcode_14.1, platform=tvOS Simulator,OS=16.1,name=Apple TV 4K (3rd generat...	4m 56s
linux (focal, 5.9)	6m 52s
apple (macos-13-xlarge, Xcode_14.1, platform=OS X)	4m 19s
linux (amazonlinux2, 5.7)	6m 42s
apple (macos-14-xlarge, Xcode_15.2, platform=iOS Simulator,OS=17.2,name=iPhone 15)	4m 54s
linux (amazonlinux2, 5.9)	6m 34s
apple (macos-14-xlarge, Xcode_15.2, platform=tvOS Simulator,OS=17.2,name=Apple TV 4K (3rd generat...	4m 24s
apple (macos-14-xlarge, Xcode_15.2, platform=OS X)	4m 13s
	55m 23s

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