#2347: GUI test duplicates view-setup code from App instead of reusing it

[Khaled-Cap]

This PR fixes #2347

Implemented changes:

• The function loadMainView() in App.java was changed to a static function with 3 Parameters: String ideRoot, GuiStateManager guiStateManager, NlsService nlsService.
• The duplicates in AppBaseTest.start() were replaced with a call of the function loadMainView().

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Testing instructions

Please add conscise, understandable instructions on how a reviewer can test/verify the functionality of your contribution here:

1. mvn clean install or simply run the tests in AppBaseTest.
2. Optional: run the class com.devonfw.ide.gui.AppLauncher to make sure the Gui can still be started correctly.

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Checklist for this PR

Make sure everything is checked before merging this PR. For further info please also see
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• When running mvn clean test locally all tests pass and build is successful
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[CLAassistant]

All committers have signed the CLA.

[coveralls]

Coverage Report for CI Build 35232602398

Coverage increased (+0.04%) to 74.202%

Details

• Coverage increased (+0.04%) from the base build.
• Patch coverage: No coverable lines changed in this PR.
• 23 coverage regressions across 2 files.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

23 previously-covered lines in 2 files lost coverage.

File	Lines Losing Coverage	Coverage
com/devonfw/ide/gui/App.java	22	14.12%
com/devonfw/tools/ide/version/VersionSegment.java	1	90.55%

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Coverage Stats

Relevant Lines:	19002
Covered Lines:	14734
Line Coverage:	77.54%
Relevant Branches:	8516
Covered Branches:	5685
Branch Coverage:	66.76%
Branches in Coverage %:	Yes
Coverage Strength:	3.31 hits per line

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💛 - Coveralls