Set fallback mode

If the registry settings are not configured, the default mode is one (1). Each number corresponds to a specific mode: (1) Normal mode (Behaves like the regular zoom client) (2) Runs as a screen share meeting (Audio and video are muted by default) (3) A pop-up appears that will say unable to meet and join (4) A dialogue prompt will display an error message. When the user closes the prompt the Zoom app will also be closed. (5) Video is disabled. (6) Video and sharing are disabled. (7) Video and computer audio are disabled