Add register memory metrics handler for memory heartbeat from host

[juanscr]

Description

This pull request adds an event handler in order for apps to receive memory metrics periodically. This will allow any app to create score cards or monitor memory usage of an app overtime, in order to diagnose any possible memory leak or regression.

Main changes in the PR:

1. Added memory event handler that app registers to it in order to get heartbeats of memory from the host.

Validation

Validation performed:

1. Tested in testing host with test app and unit tests.

Unit Tests added:

Yes.

End-to-end tests added:

No.

Additional Requirements

Change file added:

Yes

[github-actions]

size-limit report 📦

Path	Size	Loading time (3g)	Running time (snapdragon)	Total time
packages/teams-js/dist/esm/packages/teams-js/src/index.js	199.87 KB (+0.16% 🔺)	4 s (+0.16% 🔺)	267 ms (+2.61% 🔺)	4.3 s

[github-actions]

This pull request contains changes to the runtime.ts file. If you, as the author of this PR, have made changes to the Runtime interface please review RUNTIME.md to determine if a new runtime version is required. Please reply to this comment stating what changes, if any, were made to the runtime object and whether a new runtime version was required.