Redis key vault auth and 3 bug fixes

[Xeelee33]

This pull requests adds 1 new feature and 3 bug fixes.

Feature - adds key vault secret authentication option for Redis
Commit: 3368d6e
Since authenticating to Redis via managed identity is not supported in Azure Gov (Confirmed in issue #696), added a Key Vault authentication option so Gov customers can utilize Redis session caching without storing plain text access keys in Cosmos. It builds off the existing Key Vault settings in the Security tab in Admin Settings. Unlike for agents, the secret name for Redis doesn't have any specific format restrictions.

Bug fix 1 - Resolved visible text being cut off and no horizontal scroll bars in blocks in message responses
Commit: 9823912
Resolved issue described in issue #719. Confirmed that all drop downs and expansion windows like message metadata details still function properly.

Bug fix 2 - Resolved invisible icons in New Prompt editor
Commit: e4157b6
Icons were missing in Create New Prompt editor in both light and dark mode due to the SimpleMDE toolbar in the editor using Front Awesome icons that don't exist in the project. Repointed the icons to the equivalent Bootstrap icons and made necessary adjustments for dark theme.

Before

After

Bugfix 3 - Resolved conversation details not loading for legacy conversations
Commit: 5c48426
The chat_type property being called in the conversation metadata query doesn't exist in legacy conversations, so clicking on the conversation details button on legacy conversations throws an error:

This commit just adds a default value of 'personal' to chat_type when it's called but returns no value. This same logic was previously added to the conversation search function (code snippet below is from current main branch):

simplechat/application/single_app/route_backend_conversations.py

Lines 981 to 987 in fdaa3f1

	for c in conversations:
	# Default to 'personal' if chat_type is not defined (legacy conversations)
	chat_type = c.get('chat_type', 'personal')
	if chat_type in chat_types:
	filtered_in.append(c)
	else:
	filtered_out.append(c)

After the fix, the conversation details window populates properly for legacy conversations:

[paullizer]

Great additions and bug fixes!