The eslint configuration now takes the rule
`@typescript-eslint/prefer-string-starts-ends-with` [1] into account,
enforcing the usage of `startsWith()` and `endWith()` over index
checking in strings.

[1] https://typescript-eslint.io/rules/prefer-string-starts-ends-with

Resolves: #103374
Releases: main, 12.4
Change-Id: I88640f71cbe960db2a2e2b162410ff5a79e7c55c
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/83437


Tested-by: Andreas Kienast <a.fernandez@scripting-base.de>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Benjamin Franzke <ben@bnf.dev>
Tested-by: Garvin Hicking <gh@faktor-e.de>
Reviewed-by: Garvin Hicking <gh@faktor-e.de>
Reviewed-by: Andreas Kienast <a.fernandez@scripting-base.de>