Update UX to adjust display based on feature flags

[dayland]

In this PR, we have updated the UX to honor the feature flags set in local.env. The new feature flags are:

export ENABLE_WEB_CHAT=false
export ENABLE_UNGROUNDED_CHAT=false
export ENABLE_MATH_ASSISTANT=true
export ENABLE_TABULAR_DATA_ASSISTANT=true
export ENABLE_SHAREPOINT_CONNECTOR=false
export ENABLE_MULTIMEDIA=false

A bonus new flag was added ENABLE_MULTIMEDIA to disable the deployment of Azure Video Indexer until we can get multimedia support into the full UX.

[asbanger]

Thank you for latest update.