sharing larger videos not working

[r10s]

sharing a 30 seconds video on iphone7 to delta chat does not work, the thumbnail is generated and the "share dialog" is shown, however, when tapping send, sharing aborts (or crashes) and you're back to app selection screen

similar to #1330 which is fixed by #2020

[r10s]

is in #1330, the 120 mb restriction is hit. however, this time as the video is not compressed sufficiently by UI. the same 30second-test is 10 mb when sending from the app - and 60+ mb when sending from share extension. the 60 mb plus base64-overhead plus basic-extension-code hits the 120 mb then

we could try to compress videos better beforehand and check if the result probably fits - or just say that you cannot use the share extension to share videos