Add utility classes for billing plan page

.gl-text-purple-800 {
  color: $purple-800;
}

.gl-bg-theme-indigo-800 {
  background-color: $theme-indigo-800;
}

.gl-border-indigo-700 {
  border-color: $theme-indigo-700;
}

.gl-border-gray-75 {
  border-color: $gl-text-color-quaternary;
}

.gl-min-h-8 {
  min-height: $gl-spacing-scale-8;
}

Plan

• Add to gitlab-ui !2811 (merged)
• Remove from gitlab here gitlab!87116 (merged)