#9589: Save layer sourceMetadata info

[dsuren1]

Description

This PR fixes the layer's sourceMetadata not saved when exporting or saving the map

Please check if the PR fulfills these requirements

• The commit message follows our guidelines: https:/geosolutions-it/MapStore2/blob/master/CONTRIBUTING.md
• Tests for the changes have been added (for bug fixes / features)

What kind of change does this PR introduce? (check one with "x", remove the others)

• Bugfix

Issue

What is the current behavior?

• #9589: Notify data projection not compatible / available for COG #9690 (comment)

What is the new behavior?
The layer's sourceMetadata is saved properly on export and map save

Breaking change

Does this PR introduce a breaking change? (check one with "x", remove the other)

• Yes, and I documented them in migration notes
• No

Other useful information

Note for testers

Kindly DO NOT use the old map import. Add a layer from COG with metadata fetched and export it. Then try importing the same to an instance that has projectionDefs configured to test this bug and to an instance where projectionDefs are not configured to check if notification works fine

[offtherailz]

@ElenaGallo, could you please test this on DEV ? Thank you

[tdipisa]

@ElenaGallo let us know if we can backport

[ElenaGallo]

Test passed, @dsuren1 please backport this. Thanks