Replace .substr() with .substring() (or .slice()) in JS files since it's deprecated

[mykola]

Context

• Replace .substr() with .substring() in JS files since it's deprecated.

Summary

This PR can be summarized in the following changelog entry:

• Replaces .substr() with .substring() in JS files since it's deprecated.

Relevant technical choices:

• In substr second parameter is length, in substring second parameter is offset, so corresponding calculation applied to convert length to officet.
• Also substr can consume negative values - in this case it starts counting from the end of the string.

Test instructions

Test instructions for the acceptance test before the PR gets merged

This PR can be acceptance tested by following these steps:

• run unit tests and make sure that all tests pass
• do smoke test for different posts/editors to make sure that everything works as expected

Relevant test scenarios

• Changes should be tested with the browser console open
• Changes should be tested on different posts/pages/taxonomies/custom post types/custom taxonomies
• Changes should be tested on different editors (Default Block/Gutenberg/Classic/Elementor/other)
• Changes should be tested on different browsers
• Changes should be tested on multisite

Test instructions for QA when the code is in the RC

• QA should use the same steps as above.

QA can test this PR by following these steps:

Impact check

This PR affects the following parts of the plugin, which may require extra testing:

• this code can impact different part of the application so better to do smoke test to make sure that everything works as before.

UI changes

• This PR changes the UI in the plugin. I have added the 'UI change' label to this PR.

Other environments

• This PR also affects Shopify. I have added a changelog entry starting with [shopify-seo], added test instructions for Shopify and attached the Shopify label to this PR.

Documentation

• I have written documentation for this change. For example, comments in the Relevant technical choices, comments in the code, documentation on Confluence / shared Google Drive / Yoast developer portal, or other.

Quality assurance

• I have tested this code to the best of my abilities.
• During testing, I had activated all plugins that Yoast SEO provides integrations for.
• I have added unit tests to verify the code works as intended.
• If any part of the code is behind a feature flag, my test instructions also cover cases where the feature flag is switched off.
• I have written this PR in accordance with my team's definition of done.
• I have checked that the base branch is correctly set.

Innovation

• No innovation project is applicable for this PR.
• This PR falls under an innovation project. I have attached the innovation label.
• I have added my hours to the WBSO document.

Fixes #20852

[github-actions]

@mykola Please be aware that following packages have been abandoned and are not actively maintained anymore:

Package name	Path
yoast-components	packages/yoast-components
@yoast/babel-preset	packages/babel-preset
@yoast/components	packages/components
@yoast/e2e-tests	packages/e2e-tests
@yoast/helpers	packages/helpers
@yoast/jest-preset	packages/jest-preset
@yoast/style-guide	packages/style-guide

Please consider using the other packages instead.

[coveralls]

Pull Request Test Coverage Report for Build 7e98a97a6b05006022b169855d8e1944d4bdbc86

Details

• 15 of 21 (71.43%) changed or added relevant lines in 12 files are covered.
• No unchanged relevant lines lost coverage.
• Overall first build on replace-substr-with-substring-in-js-files at 56.402%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
packages/js/src/initializers/post-scraper.js	0	1	0.0%
packages/js/src/workouts/components/WorkoutsPage.js	0	2	0.0%
packages/js/src/helpers/createInterpolateElement.js	1	4	25.0%

Totals
Change from base Build 7fc2d4764c466fa860edf30577545e7b7aea6cce:	56.4%
Covered Lines:	13526
Relevant Lines:	23516

---

💛 - Coveralls

[FAMarfuaty]

All changes look good! Great job! 🙌🏽