[Bug Report][3.6.8] Custom colors transparency/opacity is ignored

[simionato-mobisec]

Environment

Vuetify Version: 3.6.8
Vue Version: 3.4.27
Browsers: Firefox 126.0
OS: Ubuntu undefined

Steps to reproduce

1. Create a custom theme.
2. Create a color named "test" with a value of "#ff000014".
3. Change VTextField defaults and set its color prop to "test".

Expected Behavior

The focused text field should have a transparent red color.

Actual Behavior

The focused text field has a red color, transparency is ignored.

Reproduction Link

https://play.vuetifyjs.com/#...

[walter-0]

Haven't confirmed yet, but I think this line is the culprit:

https://github.com/vuetifyjs/vuetify/blob/master/packages/vuetify/src/composables/theme.ts#L418

function genCssVariables (theme: InternalThemeDefinition) {
// ...
  for (const [key, value] of Object.entries(theme.colors)) {
    const rgb = parseColor(value)
    variables.push(`--v-theme-${key}: ${rgb.r},${rgb.g},${rgb.b}`) // this line is not using the 
    if (!key.startsWith('on-')) {
      variables.push(`--v-theme-${key}-overlay-multiplier: ${getLuma(value) > 0.18 ? lightOverlay : darkOverlay}`)
    }
  }
// ...
}

From doing a little bit of testing, parseColor() calls HexToRGB() which appears to be correctly converting to rgba but the value rgb.a is not being used in the string.

Should L418 be updated to this?

variables.push(`--v-theme-${key}: ${rgb.r},${rgb.g},${rgb.b},${rgb.a}`)