Better error message for type mismatch in test-utils' argument assertions

What happened?

I recently got this error message:

java.lang.AssertionError: Expected unsafe args to be {extra=[extra], missing=[missing_secret, missing_secret2]}, but found {extra=[extra], missing=[missing_secret, missing_secret_2]}

which is confusing because it looks like expected and actual are the same. Actually, their types are different -- one is a String "[extra]" and one is a Set ImmutableSet.of("extra").

In the case where two objects are different, but their toStrings() are equal, we should additionally show in the error message the types of the two objects.

This would happen here: https://github.com/palantir/conjure-java-runtime-api/blob/41e7566f4e10dcca131019a3d65d6a3b4e0beb28/test-utils/src/main/java/com/palantir/conjure/java/api/testing/ServiceExceptionAssert.java#L68

Minimal repo:

        assertThatServiceExceptionThrownBy(() -> {
                    throw new ServiceException(ErrorType.INTERNAL, UnsafeArg.of("list", ImmutableList.of("a")));
                })
                .hasArgs(UnsafeArg.of("list", "[a]"));

currently gives message:

java.lang.AssertionError: Expected unsafe args to be {list=[a]}, but found {list=[a]}

What did you want to happen?

Should return a message like:

java.lang.AssertionError: Expected unsafe args to be {list=[a]} with value type String, but found {list=[a]} with value type ImmutableList<String>

Start at test-utils/src/main/java/com/palantir/conjure/java/api/testing/ServiceExceptionAssert.java around line 68, where the unsafe-argument assertion builds its error message. Use the minimal ServiceException example to reproduce the equal-toString mismatch, then verify that differing value types appear in the message and that matching values remain readable.