#1802: fixed gui-launcher pom.xml not being included in native images on nightly/release builds.

[laim2003]

This PR fixes #1892

Implemented changes:

• Updated nightly-build and release workflows to properly generate the .flattened_pom.xml in gui-launcher before completing the assembly build. After generating, now the assembly build can properly copy the .flattened_pom.xml from gui-launcher to cli target directory, allowing the pom.xml to be included in the native images.
• The gui commandlet had a little issue leading to the commandlet to download the latest java version (e.g. 26) instead of only using the 25 version.

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• When running mvn clean test locally all tests pass and build is successful
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[coveralls]

Coverage Report for CI Build 25388299526

Coverage remained the same at 70.728%

Details

• Coverage remained the same as the base build.
• Patch coverage: No coverable lines changed in this PR.
• No coverage regressions found.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

No coverage regressions found.

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Coverage Stats

Relevant Lines:	15403
Covered Lines:	11355
Line Coverage:	73.72%
Relevant Branches:	6878
Covered Branches:	4404
Branch Coverage:	64.03%
Branches in Coverage %:	Yes
Coverage Strength:	3.12 hits per line

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💛 - Coveralls