Sync UX improvement - Conditional Device Number

[soner-yuksel]

Details at brave/brave-browser#19670 and Slack discussion.

Android ticket brave/brave-browser#32286
This is a follow up upon #4470

When connecting the sync chain, we should:
I. Don't enable by default any sync types except device info, to prevent data leak.
II. Look on the number of existing devices in the chain, excluding ours:

1..4 devices - join the chain silently and enable bookmarks
5..9 devices - show alert (are you sure) with device list; if user answers no - leave chain, if yes - enable the bookmarks type
10 and more - add alert to block and prevent sync (leave chain)

Also existing confirmation dialogs must be removed. (iOS case should remain removed)

[Uni-verse]

Verified on iPhone X running iOS 16.5.1 using version 1.58 (23.9.22.13)

Test Plan: #7918 (comment)

Case: 1-4 devices

• Ensured that device joins sync chain silently when < 4 devices connected.
• Ensured that only Device Info type is enabled by default

Example	Example

Case: 5-9 devices

• Ensured that alert is shown with device list.
• Ensured that device is not connected to chain if user selects Cancel
• Ensured that device is connected to sync chain if user selects Confirm
• Ensured that joining sync chain is successful using QR code as well as entering code words after confirming on the prompt.

Example	Example

Case: 10 devices

• Ensured Error is shown preventing user from joining chain due to maximum number of devices connected.