fix(caps): validate sha before caching features (#917)
fix(caps): validate sha before caching features (#917)

Attempts to fix this race condition:
1. Web client joins a conference.
2. Electron client joins the same conference.
3. Web client requests capabilities of Electron
   using version 1111.
4. Electron adds remote control capability,
   settings its version to 2222.
5. Electron responds to web client's requests
   but with features of 2222.
6. Web client caches request under 1111.
7. Any future calls to get features for a client
   with version 1111 will incorrect include the
   remote control capability.
jitsi/lib-jitsi-meet,damencho/lib-jitsi-meet,jiyeyuran/lib-jitsi-meet,jitsi/lib-jitsi-meet