Mediator tools for offers that aren't disputes

[bartervg]

What problem does this feature address?

When a dispute is created, mediators have a range of tools to modify an offer. For non-disputed offers, those tools don't appear and the offer state is stuck without direct database intervention.

Describe a solution

Allow mediators to join any offer except for offers they are sending or receiving.

Examples of similar features

The existing dispute tools.

[bartervg]

Mediators can join offers that they did not send or receive. However, there are several side effects.

• When the mediator joins the offer, there is an Offer Failed notice at the top, regardless of the status of the offer.
• This creates an entry on the dispute page
• The offer will appear in mediation at the top of the sender and receiver's offer page until the mediator clicks Resolved.
• Changing the failed reasons may not be useful and it's the main function available
• The other power is reset to pending / accepted, but other options needed