Adding regional api support for intercom

[pooyaj]

What does this PR do?
Adding an apiBase option for intercom. Defaulting to empty, but if user chose to pick an API region, then we will respect that value when initializing intercom.

Are there breaking changes in this PR?
No breaking change

Testing
Testing completed successfully on local using local integrations tester

Any background context you want to provide?
Intercom is adding regional support for data processing, so we are providing an option to pick region for Intercom customers.

Is there parity with the server-side/android/iOS integration components (if applicable)?
NA

Does this require a new integration setting? If so, please explain how the new setting works
Yes, we need to add apiBase to partner portal. It will be a choice between the following values:

      choices: [
        {
          label: 'US',
          value: 'https://api-iam.intercom.io'
        },
        {
          label: 'EU',
          value: 'https://api-iam.eu.intercom.io'
        },
        {
          label: 'Australia',
          value: 'https://api-iam.au.intercom.io'
        }
      ],

Links to helpful docs and other external resources
NA

[chrisradek]

Looks great! Had 1 question but it's not a blocker either way.

[chrisradek]

So Intercom isn't planning to make this required right? Wondering if we should default to the current value (US?) - what does the option look like in the app if you have 3 choices but none selected?

[pooyaj]

Actually originally added the default (https://api-iam.intercom.io) here, but then thought that's not 100% backwards compatible, because it forces users to use https://api-iam.intercom.io, while the old behavior doesn't specify the API host explicitly. Although I'm not 100% sure if defaulting to https://api-iam.intercom.io would cause any issues, but if somehow some users override the API host, and then we override it again it will be bad.

[chrisradek]

Gotcha, makes sense!