[theia] fix installing big extensions

[akosyakov]

What it does

• fix [theia] installing big extensions is broken #4025: changes in Theia: gitpod-io/theia-app@1ca36af

How to test

• Switch to Theia.
• Start a workspace and try to install big extensions like Java.
• Test the same on staging against GCP storage: https://github.com/gitpod-com/gitpod/pull/5295

[jankeromnes]

Many thanks for fixing this! Taking a look now. 👀

[jankeromnes]

Code change looks good! (And is much easier to review with ?w=1 at the end of the diff URL.)

It also works as advertised in both core and io. ✅

Two questions out of curiosity:

• @akosyakov While debugging this, did you see a more relevant error message than just "upload failed" anywhere that could explain why exactly installing "big" extensions started failing? (E.g. was fs.readFileSync() throwing for some reason?)

• @corneliusludmann What exactly was the problem with HTTP redirects that prompted the rewrite from stream to fs.readFileSync() in Support HTTP redirect in plugin deployer theia-app#2? (I.e. since this PR essentially reverts this part, I'd like to make sure it doesn't regress whatever was fixed by Support HTTP redirect in plugin deployer theia-app#2.)

[corneliusludmann]

• @corneliusludmann What exactly was the problem with HTTP redirects that prompted the rewrite from stream to fs.readFileSync() in gitpod-io/theia-app#2? (I.e. since this PR essentially reverts this part, I'd like to make sure it doesn't regress whatever was fixed by gitpod-io/theia-app#2.)

It simply didn't work for me with the HTTP redirect. I wasn't able to upload any plugins. Don't know why. If it works know it's great and I'm fine with it!