This PR adds a new theme variable for team sidebar text which would replace the currently constructed colour of the team bar, inclusive of channelHeaderColour + opacity.
@devinbinnie @hmhealey the theme was getting updated and overwritten by the default theme in multiple places in the code, so I think its best to keep it all in the 'getTheme' selector.
Summary
This PR adds a new theme variable for team sidebar text which would replace the currently constructed colour of the team bar, inclusive of channelHeaderColour + opacity.
Ticket Link
https://mattermost.atlassian.net/browse/MM-32087