Make library interoperable with Svelte 5

[metonym]

Review by commit – rebase merge.

https://github.com/carbon-design-system/carbon-components-svelte/discussions/1908

There are several low-lift revisions that make this library interoperable with Svelte 5.

• fix: avoid using reserved $ for Svelte 5 compat
• fix(link)!: do not render p for disabled link (Closes #1924)
• fix(search): hoist ignore a11y autofocus comment

[theetrain]

Fix was released in v0.83.0.