Fix issues with sweetalert2 v11

[mifi]

After upgrading to sweetalert2 in #785 and doing some testing, I noticed a few (potentially breaking) changes:

overflow of content

Go to Tracks ,then click the "I" for one track and see that the content overflows the whole sweetalert container if too large, even though overflow: auto on the content.

This info box: https://github.com/mifi/lossless-cut/blob/a9bc6c555b410fbeb8bb65df2878d1c530591a54/src/StreamsSelector.jsx#L169

With sweetalert2 v10 it loks like this:

Not sure how to best fix this, maybe you have some thoughts @limonte ?

text invisible inside alert

text color for inputs (radio) in sweetalert2 now inherits from body. losslesscut has white body color, so the text now becomes invisible.

• [x] Not sure if it's the "correct" way to do it, but setting black text for swal2-container works:

.swal2-container {
  color: black;
}

[limonte]

Sorry for missing those details @mifi! Both of them actually look like issues that should be fixed on the sweetalert2's side. I will check that right away.

[mifi]

Thanks, this is now resolved