stylelint-config: Resolve nested selectors with selector-class-pattern

[aduth]

🎫 Ticket

Partially addresses #10545 (cc @anselmbradford)

🛠 Summary of changes

Updates Stylelint configuration to specify optional resolveNestedSelectors property of the configured selector-class-pattern rule.

📜 Testing Plan

Verify yarn lint:css passes.

Optional: Validate that interpolated selector names consistently enforce the selector name validation:

Example:

diff --git a/app/javascript/packages/document-capture/components/_file-input.scss b/app/javascript/packages/document-capture/components/_file-input.scss
index 8967e4e1f9..8dcafd7c8e 100644
--- a/app/javascript/packages/document-capture/components/_file-input.scss
+++ b/app/javascript/packages/document-capture/components/_file-input.scss
@@ -10,2 +10,10 @@
   outline-offset: 2px;
+
+  &--foo {
+    color: red;
+  }
+
+  &__foo {
+    color: red;
+  }
 }

$ yarn lint:css
yarn run v1.22.22
$ stylelint 'app/assets/stylesheets/**/*.scss' 'app/javascript/**/*.scss' 'app/components/*.scss'

app/javascript/packages/document-capture/components/_file-input.scss
 16:3  ✖  Class selectors should be named using "Two Dashes Style" BEM format. See:                                 selector-class-pattern
          https://en.bem.info/methodology/naming-convention/#two-dashes-style

[aduth]

Published to NPM as @18f/identity-stylelint-config@4.1.0

https://www.npmjs.com/package/@18f/identity-stylelint-config