Element Call integration into Mainline Apps -- Element Web / Desktop

[fkwp]

This is an epic issue. List of individual issues is below:

Highlevel Overview

This epic lists the tickets to integrate Element Call (which is based on WebRTC) into the mainline applications Element Web and Element Desktop

Recent web-browser engines comprise a decent WebRTC implementation as well as (audio / video) media handling. On top of that stack Element Call was developed implementing scalable decentralised E2EE group voice and video calling (MSC3401). For the sake of time, MSC3401 is integrated into the mainline applications as a widget, but sharing the host app's Matrix client, on all 3 platforms embedding Element Call.

Note the native integration MSC3401 is at the current point in time out of scope.

Linked Issues

• implementation is done MSC3819: Allowing widgets to send/receive to-device messages matrix-org/matrix-spec-proposals#3819
• Reach 80% test coverage on JS-SDK group call PR matrix-org/matrix-js-sdk#2552
• Make video rooms work with Element Call element-web#22964
• Convert JavaScript to TypeScript in Element Call #330
• Element Call Matroska mode #486
• Typescript strict mode #558
• handle mutliple group calls in a room in some way, eg. always join the most recently added Edit matrix-org/matrix-js-sdk#2589
• Implement the new group call designs (Element Call) 1/2 element-web#23107
• Implement the new group call designs (Element Call) 2/2 element-web#23453
• Invite button in EC video rooms doesn't work element-web#23335
• Virtual widgets show up in the room info panel element-web#23494
• Hide screen-sharing button in Element Call on desktop matrix-org/matrix-react-sdk#9423
• Hide virtual widgets from the room info panel matrix-org/matrix-react-sdk#9424
• Better accommodate long room names in call toasts matrix-org/matrix-react-sdk#9426
• Invite button in EC video rooms doesn't work element-web#23335

[Thatoo]

For parity with Element Call in web browser, it is missing the screen share option (full screen or app screen).