Fix sidenav height and padding by updating Docsy

[chalin]

Context:

• Update Docsy to bring in Fix left-nav height and padding google/docsy#1661 once it lands
• Remove:

  opentelemetry.io/assets/scss/_styles_project.scss

  Lines 106 to 108 in ad9ebd5

  	.foldable-nav {
  	padding-top: 0.5rem;
  	} // TODO: propagate this fix to Docsy. Also class name should be prefixed with td

[chalin]

Fixed by:

• [forthcoming PR]

Screenshots:

Before	After