Link to existing conversation by ID or search dialog

Currently, the only way to link existing conversations is with Mass linking (selecting multiple conversations in the conversation list).

Linking existing conversations is impractical and difficult for users if the conversations do not already exist together in a conversation list, and/or can not reasonably be located together via common search terms.

Further, the current workflow of "Create linked conversation" supports the case when the Front user is sending a new, separate message to a vendor or contact, but not the inverse, where the new message originates from the vendor or contact.

Proposed idea is to add a "Link to existing conversation" option in the 3-dot menu adjacent to "Create linked conversation."

Selecting could present a dialog, accepting either a Conversation ID, and/or showing a search input to lookup the other conversation.

Once a conversation is selected, and before confirmation, the user would have an opportunity to indicate which conversation is the Original.