[torconnect] Add initial "Connect to Tor" tab to breadcrumb

In the latest iteration of Connection Assist's design in #40781 (comment 2794457), I added Connect to Tor as the first tab in the breadcrumb sequence. This is to help facilitate backwards navigation after a failed attempt at a regular connection, and is intended as a more permanent solution to simply renaming the "Connect" button to "Try Again" in #40874 (closed):

Notes:

• After the first attempt fails, users should still be forwarded to Connection Assist – i.e. the second tab in the sequence.
• Connect to Tor should also remain breadcrumbless by default as per the designs in #40780 (closed), unless Connection Assist has been fired up in response to a connection error.
• Once users are able to navigate back to Connect to Tor using the breadcrumb, the Connect/Try Again button may be removed from the Connection Assist tab.

The intended UX can be demo'd using this prototype too: Figma prototype