refactor(toolbar): enhance toolbar mounting and cleanup process

[pranjal-jately-ld]

Includes adding tests for toolbar mounting and cleanup process.

Description

What does this PR do?

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to not work as expected)
• 📚 Documentation (changes to documentation only)
• 🔧 Refactor (code change that neither fixes a bug nor adds a feature)
• 🎨 Style (formatting, missing semicolons, etc; no production code change)
• ⚡ Performance (code change that improves performance)
• ✅ Test (adding missing tests, refactoring tests; no production code change)
• 🔨 Chore (updating grunt tasks, build process, etc; no production code change)

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Screenshots/Videos

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