fixed incorrect return type of Searcher.searchOne

[sdellysse]

Description

## Changes Return type of Searcher.searchOne was incorrect, fixed. Also fixed deprecation notice for Searcher.findById pointing to nonexistant function. ## Checks - [X] Project Builds - [X] Project passes tests and checks - [X] Updated documentation accordingly

[what-the-diff[bot]]

PR Summary

• Update in findById Method of Searcher Class The method for searching for specific content in our system, findById, has been refined. We are moving away from the previous method of searcherFunction to a more efficient approach using searchOne.

• Change in Return Type of searchOne Method There's an update to what the searchOne method can potentially return. Apart from existing values, it could now also return undefined, basically indicating that no matching result was found. This enhancement can be beneficial in the event no match is identified, assisting in error handling and providing more precision in search results.

[MarcAstr0]

Closing this PR since changes have been incorporated to PR #1404