test: use go 1.23

[eliobischof]

Uses go v1.23 to run the testsuite.

Even though this code is not meant to be imported and therefore this change is IMO not necessary according to zitadel/zitadel#8906 because it already uses a supported go version, it can't hurt to upgrade it anyway.

Definition of Ready

• I am happy with the code
• Short description of the feature/issue is added in the pr description
• PR is linked to the corresponding user story
• Acceptance criteria are met
• All open todos and follow ups are defined in a new ticket and justified
• Deviations from the acceptance criteria and design are agreed with the PO and documented.
• No debug or dead code
• My code has no repetitions
• Documentation/examples are up-to-date
• All non-functional requirements are met
• If possible, the test configuration is adjusted so acceptance tests cover my changes

[eliobischof]

@muhlemmer did I misunderstand the issue or is it fine like this?

[muhlemmer]

Looks good to me!