fix(components): include mode classes on components for use in shadow (#17838)

- removes mode-less component classes from the internal CSS, use element instead
- adds mode specific classes `md` or `ios` for styling inside of shadow components
- adds e2e test that verifies mode classes exist on all ionic components, plus checks for specific classes that the components need for internal styling

fixes #17608

core/src/components/slides/slides.scss

@@ -4,7 +4,7 @@
 // Slides
 // --------------------------------------------------
 
-.slides {
+ion-slides {
   /**
    * @prop --bullet-background: Background of the pagination bullets
    * @prop --bullet-background-active: Background of the active pagination bullet