Split by '.' only once when parsing 'dataSource' for a text resource variable

[martinothamar]

Description

Make sure we only split dataSource by . once, so that if there are datatypes with the . character we still use the full datatype string when resolving datamodel references for variable substitution in text resources.

This was discovered by brreg dev, ref Slack thread: https://altinn.slack.com/archives/C02EJ9HKQA3/p1733736458716249

Related Issue(s)

• N/A

Verification/QA

• Manual functionality testing
  • I have tested these changes manually
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  • No testing done/necessary
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  • No automatic tests are needed here (no functional changes/additions)
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• UU/WCAG (follow these guidelines until we have our own)
  • I have tested with a screen reader/keyboard navigation/automated wcag validator
  • No testing done/necessary (no DOM/visual changes)
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  • Has been added/updated
  • No functionality has been changed/added, so no documentation is needed
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  • This change/feature does not require any changes to Altinn Studio
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• Labels
  • I have added a kind/* label to this PR for proper release notes grouping
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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
72.2% Coverage on New Code
0.0% Duplication on New Code

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