Refactor FXIOS-10897 [Bookmarks Evolution] Remove Deferred usage from BookmarksSaver

[PARAIPAN9]

📜 Tickets

Jira ticket
Github issue

💡 Description

• Replace Deferred with Result type completion handler.
• Tests Pass

📝 Checklist

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• Filled in the above information (tickets numbers and description of your work)
• Updated the PR name to follow our PR naming guidelines
• Wrote unit tests and/or ensured the tests suite is passing
• When working on UI, I checked and implemented accessibility (minimum Dynamic Text and VoiceOver)
• If needed, I updated documentation / comments for complex code and public methods
• If needed, added a backport comment (example @Mergifyio backport release/v120)

[mobiletest-ci-bot]

	Messages
📖	Project coverage: 34.46%
📖	Edited 4 files
📖	Created 0 files

Client.app: Coverage: 32.5

File	Coverage
BookmarksSaver.swift	95.72%	✅

libStorage.a: Coverage: 56.87

File	Coverage
RustPlaces.swift	81.29%	✅

Generated by 🚫 Danger Swift against 20f9ae7

[lmarceau]

@PARAIPAN9 I think there was a new function added in BookmarksSaver called restoreBookmarkNode. We should remove Deferred from there as well. Could you have a look? 🙏

[mergify]

This pull request has conflicts when rebasing. Could you fix it @PARAIPAN9? 🙏