Bug: Error banner flashes on read-only boards

[chenilim]

Steps to reproduce the behavior

1. Open a board
2. Enable share-board from the board menu
3. Copy the link and paste it in a new window
4. The error banner flashes while the board loads

Expected behavior

No error banner flash

Screenshots

error.banner.flash.mov

Edition and Platform

• Edition: Mattermost plugin
• Version: v0.11 RC2
• Browser and OS: Chrome on macOS

Additional context

This problem existed in 0.10 (and possibly earlier), but is a regression from earlier versions.