Add network connectivity integration tests

[JakubJankowski]

Recently Android AAT SDK introduced a suite of tests related to the sdk's behaviour in unstable network conditions - see NetworkConnectivityTests.kt

We should introduce a similar set of tests, and of course make sure that the sdk works according to the tests' specs.

[sync-by-unito[bot]]

➤ Automation for Jira commented:

The link to the corresponding Jira issue is https://ably.atlassian.net/browse/SDK-3323

[lawrence-forooghian]

I've broken this work down into the following; it will be complete when these are complete:

• https://github.com/ably/ably-asset-tracking-swift/issues/537
  • depends on https://github.com/ably/ably-asset-tracking-android/issues/1003, which depends on:
  • https://github.com/ably/sdk-test-proxy/issues/2
  • https://github.com/ably/sdk-test-proxy/issues/3
  • https://github.com/ably/sdk-test-proxy/issues/4
• https://github.com/ably/ably-asset-tracking-swift/issues/538
• https://github.com/ably/ably-asset-tracking-swift/issues/574
• https://github.com/ably/ably-asset-tracking-swift/issues/541
• https://github.com/ably/ably-asset-tracking-swift/issues/539
• https://github.com/ably/ably-asset-tracking-swift/issues/575
• https://github.com/ably/ably-asset-tracking-swift/issues/540