fix(label-upload): add error handler for metadata uploads

[tthvo]

Fixes #623

Handled parsing error if user uploads invalid metadata label files. The invalid files are shown in a popover on top of the button since inline texts are taking quite some spaces and misaligned. In the background, invalid file contents are ignored (i.e. return empty []).

[tthvo]

Any thoughts on this design?

[andrewazores]

Design looks good. I think the two texts are mostly saying the same thing though, so either one should be rephrased or the one inside the component body should be removed.

Maybe,
title: "Invalid Selection"
message: "The following files did not contain valid recording metadata:"

[andrewazores]

Code looks good

[tthvo]

I think the two texts are mostly saying the same thing though, so either one should be rephrased or the one inside the component body should be removed.

Nice! Thanks I updated the modal now.

[andrewazores]

LGTM, I'll give @maxcao13 a chance to look at this too