Initially open dropdowns don't have event handlers attached (e.g. close on document click)

[43081j]

Describe the bug

With an already open dropdown, clicking outside the container will not close it. That and all other event handlers attached in the open observer will not have run.

To Reproduce

Steps to reproduce the behavior:

      <sl-dropdown open>
        <sl-button slot="trigger" caret>Toggle</sl-button>
        <sl-menu>
          <sl-menu-item>Item 1</sl-menu-item>
        </sl-menu>
      </sl-dropdown>

Run this somewhere and click outside the dropdown, it won't close.

Click the dropdown, then reopen it, and clicking outside it will now close it.

Additional information

shoelace/src/components/dropdown/dropdown.ts

Lines 336 to 337 in 68603f9

	@watch('open', { waitUntilFirstUpdate: true })
	async handleOpenChange() {

Within this observer, various event handlers are attached amongst other things.

None if this will run if the dropdown is initially open (presumably due to waitUntilFirstUpdate), meaning things like "close on document click" will not work.