fix(VChip, VTab): render inner wrappers as phrasing content

[BatLeDev]

Description

fixes #23103

Two components render non-phrasing content inside a span, producing the same W3C error:

Element “div” not allowed as child of element “span” in this context.

VChip defaults its root tag to span, so everything it renders inside must be phrasing content. Four wrappers were hardcoded as div — v-chip__filter, v-chip__prepend, v-chip__content and v-chip__append — so every chip was invalid on its own, anywhere on the page. Unlike the same class of defect on VBadge (#23093), there is no tag default to debate here, since the root is already a span.

All four are now span, which is what the sibling v-chip__overlay and v-chip__underlay wrappers already were.

VTab renders its underline as a hardcoded div.v-tab__slider inside VBtn's default slot, which VBtn wraps in a span.v-btn__content — so every tab emits a div inside a span too. It is now a span. Repro: https://vtfy.link/vtab-slider-invalid-nesting

No visual change in either case. VChip.sass declares display: inline-flex explicitly on .v-chip__content and on the .v-chip__filter/.v-chip__prepend/.v-chip__append group, and .v-tab__slider is position: absolute, which blockifies the box whatever the tag name. v-chip__filter is the only wrapper inside a VExpandXTransition; its display is declared the same way, and the added test covers it. The chip's close button is untouched — it is a button element, already valid phrasing content.

None of these elements is reachable from userland (tag only controls the root, and for VTab the root of the underlying VBtn), so there was no workaround short of patching the package.

Added a test per component: the chip root is a span whose subtree contains no div, with filter, prepend and append all rendered; and the tab's v-btn__content contains the slider and no div.

Happy to split this back into two PRs if you'd rather keep them separate.

Markup:

<template>
  <v-app>
    <v-container>
      <v-chip prepend-icon="mdi-tag" text="Plain chip" />
      <v-chip append-icon="mdi-close" text="With append" />
      <v-chip-group filter>
        <v-chip text="Filterable" />
      </v-chip-group>

      <v-tabs v-model="tab">
        <v-tab value="one" text="One" />
        <v-tab value="two" text="Two" />
      </v-tabs>
    </v-container>
  </v-app>
</template>

<script>
  export default {
    name: 'Playground',
    setup () {
      return {
        tab: 'one',
      }
    },
  }
</script>

Run the rendered page through https://validator.w3.org/nu — one div-inside-span error per chip and per tab before, none after.