[ACTIONS] Add back button to add / edit flyouts

[cnasikas]

Describe the feature:

It would be nice to have a back button when creating or updating an action (connector). The button can navigate you to the initial screen where all the connectors are presented.

EDIT

The cancel button at the bottom of the flyout could be replaced with the back button.

Use cases without the back button:

Below the user made a mistake and selected ServiceNow instead of Jira.

Describe a specific use case for the feature:

A user made a mistake and clicked the wrong connector. She pressed the back button and returns to the screen where all connectors are presented.

[elasticmachine]

Pinging @elastic/kibana-alerting-services (Team:Alerting Services)

[ymao1]

If we replace the 'Cancel' button with 'Back', if the user selects a connector type and then decides she doesn't want to add a connector, it will take two clicks ("Back" then "Cancel") to close the flyout. Is that acceptable? @cnasikas @elastic/kibana-alerting-services

[cnasikas]

Hi! The user can press the X button at the top right if she wants to cancel, with one click. What do you think;

[ymao1]

Ah gotcha! I didn't notice the X button, but you are right! Thanks for pointing that out. Sounds good to me.