Update release CI scripts

[Arctis-Fireblight]

Summary by CodeRabbit

• Chores
  • Enhanced CI/CD pipeline with automatic cleanup of build artifacts and refined conditional release execution to ensure more reliable and controlled release builds.

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[coderabbitai]

Walkthrough

This change modifies the GitLab CI configuration to add cleanup steps that remove build artifacts (bin/obj directory) after build stages and converts job execution conditions from unconditional to release-gated using conditional rules ($DO_RELEASE == "true") for specific Linux editor build jobs.

Changes

Cohort / File(s)	Summary
CI/CD Pipeline Configuration .gitlab-ci.yml	Added cleanup steps removing build artifacts (rm -rf bin/obj) across multiple stages; changed job execution rules from when: always to conditional if: $DO_RELEASE == "true" for linux-editor-x64-mono and linux-editor-x64 jobs; minor formatting adjustments to version logic blocks with no functional alteration to version string generation

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Possibly related PRs

• Redot-Engine/redot-engine#1145: Introduces the full CI pipeline structure that this PR modifies with cleanup steps and conditional rules.

Suggested labels

topic:buildsystem

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'Update release CI scripts' accurately describes the main change—modifications to the CI/CD pipeline in .gitlab-ci.yml for release builds, including cleanup steps and conditional execution logic.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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