View SSM Sessions: assume/inherit configured region

[rawiriblundell]

Describe the bug
When using View SSM Sessions against a Session that has a configured region, the SSM Session viewer should automatically use that region.

Leapp Version
0.12.2

To Reproduce
Steps to reproduce the behavior:

1. Right Click on a saved Session
2. Click on 'View SSM Sessions' (Or: click on the View SSM Sessions button on the bottom toolbar)
3. Think "WTH?" when you get challenged for a region, even though the Session has a configured region
4. Manually select the region that you've already configured, ruing the day (though fuzzy-finding it is nice)
5. SSM Session Viewer fetches the available instances

Expected behavior

1. Right Click on a saved Session
2. Click on 'View SSM Sessions' (Or: click on the View SSM Sessions button on the bottom toolbar)
3. SSM Session Viewer automatically fetches the available instances from the configured region

People using multiple regions can then switch to their secondary/tertiary/etc regions as required, or setup region-specific saved Sessions.

Screenshots

Desktop (please complete the following information):

• OS: Windows
• OS Version 11
• Leapp Version 0.12.2

Additional context
For those of us using 1-2 regions - especially non-US ones - having to filter through all of the regions is a little obnoxious, so I consider this to be somewhat related to #205 - and perhaps there's a common solution.

[andreacavagna01]

Yeah I think it's related, it's a bug and can be solved easily in the next releases