Added a unit test for checking cloze counter numbering while toggling.

[Alok-Silswal]

Purpose / Description

While solving #20350 issue and working with #20398 PR, I noticed that there is no unit test that checks if the cloze counter number is correct while toggling mode (from INCREMENT to NO_INCREMENT and vice-versa).

It is the by-product of observations as mentioned in #20350 (comment)

As a result of the absence of this unit test, even an incorrect implementation(intermediate code I used while testing) is passing all the unit tests.

Fixes

• Related to Adding additional clozes doesn't work properly for Instant Cards in AnkiDroid #20350

Approach

It checks if the cloze counter number is assigned the correct value when we switch modes each time, by creating a unit test.

How Has This Been Tested?

This test fails on main but passes with fix made in #20398 PR.

Checklist

• You have a descriptive commit message with a short title (first line, max 50 chars).
• You have commented your code, particularly in hard-to-understand areas
• You have performed a self-review of your own code
• UI changes: include screenshots of all affected screens (in particular showing any new or changed strings)
• UI Changes: You have tested your change using the Google Accessibility Scanner

[Alok-Silswal]

@david-allison Submitting this as a separate PR to keep the original fix focused and instructions as given in #20398 (comment) i.e.

When you're bugfixing, keep the commit as lean as possible:

• fix
• test

If you notice more tests could be added, feel free to either add them as a new commit, or raise a separate PR. No issue necessary

This change only adds additional test coverage for toggle behaviour.