Make it possible to return raw fields in search results

[gerzse]

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Description of change

In some use cases (e.g. vector search), the fields in the search results must not be decoded. Add an optional parameter to the search methods, which makes it possible to disable decoding.

In order to not break the existing functionality, the parameter has the default value set to True, i.e. it will decode like before.

Fixes #2772

[bsbodden]

@gerzse I would reference the original bug report in the PR #2772

Otherwise it looks good to me! Other than run the linters locally to appease the formatting gods!

[gerzse]

This is superseded by #3309