[GSoC] Filter Sheet: Create function to retrieve names of all models

[viciousAegis]

Pull Request template

Purpose / Description

Create a function to return the names of all the note models being used

Fixes

Fixes Link to the issues.

Approach

Create a new function to return a list of names of all the models

How Has This Been Tested?

TODO
Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration (SDK version(s), emulator or physical, etc)

Learning (optional, can help others)

Describe the research stage

Links to blog posts, patterns, libraries or addons used to solve this problem

Checklist

Please, go through these checks before submitting the PR.

• You have not changed whitespace unnecessarily (it makes diffs hard to read)
• You have a descriptive commit message with a short title (first line, max 50 chars).
• Your code follows the style of the project (e.g. never omit braces in if statements)
• 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

[viciousAegis]

@ankidroid/gsoc-mentor allNames() function ready for review