Uploading image for groupchat: Error: ERROR CODE 200

This is the error code I get when I try to upload an image for a group chat:
```Error: ERROR CODE 200 - RPC error 200: Error: couldn't handle in method keybase.1.teams.uploadTeamAvatar at new r (file:///Applications/Keybase.app/Contents/Resources/app/desktop/dist/index.bundle.js:1:441228) at file:///Applications/Keybase.app/Contents/Resources/app/desktop/dist/index.bundle.js:1:441757 at u (file:///Applications/Keybase.app/Contents/Resources/app/desktop/dist/index.bundle.js:1:441796) at _rpcClient.invoke.t (file:///Applications/Keybase.app/Contents/Resources/app/desktop/dist/index.bundle.js:1:245338) at file:///Applications/Keybase.app/Contents/Resources/app/desktop/dist/index.bundle.js:1:1758890 at e.t.Deferrals.e._call (file:///Applications/Keybase.app/Contents/Resources/app/desktop/dist/index.bundle.js:1:1649609) at file:///Applications/Keybase.app/Contents/Resources/app/desktop/dist/index.bundle.js:1:1649760 at s (file:///Applications/Keybase.app/Contents/Resources/app/desktop/dist/index.bundle.js:1:1649389) at e.t.Deferrals.e._fulfill (file:///Applications/Keybase.app/Contents/Resources/app/desktop/dist/index.bundle.js:1:1649719) at s (file:///Applications/Keybase.app/Contents/Resources/app/desktop/dist/index.bundle.js:1:1648923)```

This is the version I'm currently running:
`Version 2.5.0-20180807174114+6435f04df6 (2.5.0-20180807174114+6435f04df6)`

Please let me know if you need any more info.

Start by reproducing the group-chat image upload failure in the desktop client and trace the keybase.1.teams.uploadTeamAvatar entry point named in the error. The reported failure occurs in Applications/Keybase.app/Contents/Resources/app/desktop/dist/index.bundle.js, so identify the corresponding source implementation and determine whether the upload succeeds after the error is addressed.

Written by the indexing model from the issue text.