Improve tests to use ApplicationContextRunner

[MatejNedic]

:loudspeaker: Type of change

• [ ] Bugfix
• [ ] New feature
• [x] Enhancement
• [x] Refactoring

:scroll: Description

Tests refactored : ContextInstanceDataAutoConfigurationTest, ContextResourceLoaderAutoConfigurationTest and AwsSecretsManagerBootstrapConfigurationTest

:bulb: Motivation and Context

closes #676

:green_heart: How did you test it?

:pencil: Checklist

• [x] I reviewed submitted code
• [ ] I added tests to verify changes
• [ ] I updated reference documentation to reflect the change
• [x] All tests passing
• [ ] No breaking changes

:crystal_ball: Next steps