Bug - File upload multiple - allow ability to change button text

[simrandhaliw]

The 'Upload' button text in the 'File upload - multiple' PF component is hardcoded and cannot be changed.

I expect to be able to change the button text. E.g., label it as 'Browse' instead of 'Upload'.

Currently, this is not a blocker.

I am trying to use this component for a feature in Apicurio Registry. We are expecting to implement this feature in Q4.

[nicolethoen]

Closed by #9275