Final batch of new autofill pixels

[amddg44]

Task/Issue URL: https://app.asana.com/0/1203822806345703/1207602891714014/f
Tech Design URL:
CC:

Description:
Final autofill pixels implemented (mostly related to credential management in the UI)

Steps to test this PR:

1. In XCode console log, filter for m.autofill.management
2. Launch the app and access the Passwords screen via the tab bar ... menu
3. Confirm the pixel m.autofill.management.opened fires with parameter ["source": "overflow_menu"]
4. In the passwords screen create a new login with any username & password
5. Confirm the pixel m.autofill.management.save.login is fired
6. Edit and save the login
7. Confirm the pixel m.autofill.management.update.login is fired
8. Tap the copy button next the username
9. Confirm the pixel m.autofill.management.copy.username is fired
10. Tap the copy button next the password
11. Confirm the pixel m.autofill.management.copy.password is fired
12. From the same screen delete the login
13. Confirm the pixel m.autofill.management.delete.login is fired (once the delete undo toast disappears)
14. Create another new login (if you don't have any saved) and go back to the Passwords screen
15. Tap the menu button from the navigation bar and select Edit
16. Delete a single row
17. Confirm the pixel m.autofill.management.delete.login is fired (once the delete undo toast disappears)
18. Create another new login (if have none saved)
19. Tap the menu button from the navigation bar and select Edit
20. Tap Delete All from the toolbar
21. Confirm the pixel m.autofill.management.delete.all.logins is fired (once the delete all undo toast disappears)
22. Back out of the Passwords screen and come back in via the Settings screen
23. Confirm the pixel m.autofill.management.opened fires with parameter ["source": "settings"]
24. Minimise the app, long press on the app icon and select Search Password
25. Confirm the pixel m.autofill.management.opened fires with parameter ["source": "app_icon_shortcut"]
26. Add the Search Passwords home screen widget and tap it
27. Confirm the pixel m.autofill.management.opened fires with parameter ["source": "home_screen_widget"]
28. Add the Search Passwords lcok screen widget and tap it
29. Confirm the pixel m.autofill.management.opened fires with parameter ["source": "lock_screen_widget"]

---

Internal references:

Software Engineering Expectations
Technical Design Template