Fix the capitalization of property for S3EncryptionConditional.KmsKeyProperty

[gbaso]

📢 Type of change

• Bugfix
• New feature
• Enhancement
• Refactoring

📜 Description

Changes the capitalization of the property for S3EncryptionConditional.KmsKeyProperty from spring.cloud.aws.s3.encryption.keyId to spring.cloud.aws.s3.encryption.key-id. Adds a test that verifies the creation of an S3EncryptionClient when setting that property.

💡 Motivation and Context

Fixes gh-1333

💚 How did you test it?

Unit tests, manual tests with a sample application.

📝 Checklist

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

🔮 Next steps

[maciejwalkowiak]

Thanks @gbaso!