Fix ClassCastException for valueMatches in AddOrUpdateAnnotationAttribute

[jevanlingen]

What's changed?

Improved check to be sure no ClassCastException can occur.

What's your motivation?

If an Unknown typed JavaType is used as constant, a

Caused by: java.lang.ClassCastException: class org.openrewrite.java.tree.J$FieldAccess cannot be cast to class org.openrewrite.java.tree.J$Identifier (org.openrewrite.java.tree.J$FieldAccess and org.openrewrite.java.tree.J$Identifier are in unnamed module of loader 'app')

is thrown.

Checklist

• I've added unit tests to cover both positive and negative cases
• I've read and applied the recipe conventions and best practices
• I've used the IntelliJ IDEA auto-formatter on affected files