Add aria labels for browse files buttons

[corivera]

For #25129

Adds a "Browse files" aria label for browse buttons that only have an ellipsis label ('...').

[coveralls]

Pull Request Test Coverage Report for Build 7618049208

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• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.002%) to 41.758%

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Totals
Change from base Build 7617774614:	-0.002%
Covered Lines:	30827
Relevant Lines:	69081

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💛 - Coveralls