Remove Spring Security class dependency on ProblemAutoConfiguration

[cberg-zalando]

Description

0.26.0 changed the way how the default ExceptionHandling implementation is instantiated. As we have projects, which switched to Fabric Gateway for authentication and in consequence removed Spring Security dependencies, the latest version of the library does not work as in this case the class WebSecurityConfigurer is not available on the classpath.

Motivation and Context

Fixes dependent projects not using Spring Security due to changes introduced in #413.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.

[whiskeysierra]

👍

[whiskeysierra]

Released as 0.26.1. Thanks for the fix! 🎉