fix(VField): correct outline label position for tile variant

[waterWang]

Description

Fixes #22269

The [class^="rounded-"] CSS selector was also matching the rounded-0 class (applied by the tile prop), which caused the outline __start element to get a wider flex-basis intended for rounded corners.

Root Cause

In VField.sass, the outline __start element has these rules:

1. Default: flex: 0 0 $field-control-affixed-padding (12px)
2. Override for rounded: flex-basis: calc(var(--v-input-control-height) / 2 + 2px) (≈30px)

The override selector [class^="rounded-"] matches rounded-0 (tile), causing the __start to be 30px wide when it should be 12px. This shifts the notch and label to the right.

Fix

Added an explicit override for .rounded-0 to restore the correct $field-control-affixed-padding (12px) flex-basis, so the label properly aligns with the outline border on tiled fields.

Reproduction

<template>
  <v-app>
    <v-container>
      <v-text-field
        model-value="Hi!"
        label="Label"
        variant="outlined"
        hide-details
        tile
      />
      <v-text-field
        model-value="Hi!"
        label="Label"
        variant="outlined"
        hide-details
      />
    </v-container>
  </v-app>
</template>

The first field (tiled) has the label slightly misaligned (too far right). After the fix, both fields have correctly aligned labels.