[Embed block] Can't set URL after dismissing the edit URL bottom sheet with empty value

[fluiddot]

Describe the bug
On an empty embed block, the edit URL bottom sheet is no longer displayed if it was previously dismissed with an empty URL, leaving the block unusable.

This issue was introduced in #4002.

To Reproduce

1. Add an embed block via the block picker
2. Observe that the edit URL bottom sheet is automatically displayed
3. Dismiss the bottom sheet
4. Tap on the embed block
5. Observe that the edit URL bottom sheet is displayed
6. Dismiss the bottom sheet again
7. Tap on the embed block again
8. Observe that the edit URL bottom sheet is NOT displayed

Expected behavior
The edit URL bottom sheet should be always displayed when tapping on empty embed blocks.

Screenshots

embed-block-edit-url-issue.mp4

Smartphone (please complete the following information):

• Device: iPhon 12 Pro Max
• OS: iOS 14.5
• Version 18.4

Additional context
N/A

[fluiddot]

I noticed that this issue can be also reproduced when dismissing using an invalid URL.

Steps:

1. Dismissing with invalid URL
2. Add an embed block via the block picker
3. Observe that the edit URL bottom sheet is automatically displayed
4. Dismiss the bottom sheet
5. Tap on the embed block
6. Observe that the edit URL bottom sheet is displayed
7. Set an invalid URL (example: http://?)
8. Dismiss the bottom sheet again
9. Observe that an error notice is shown
10. Tap on the embed block again
11. Observe that the edit URL bottom sheet is displayed again