Remove "dsa-1024" testcases from Test_SSHParsePublicKey and Test_calcFingerprint...

Remove "dsa-1024" testcases from Test_SSHParsePublicKey and Test_calcFingerprint (#31905)

DSA is considered inherently insecure and is already disabled/removed in
OpenSSH 9.8.

Therefore "dsa-1024" tescases are failing.

```
--- FAIL: Test_calcFingerprint (0.02s)
    --- FAIL: Test_calcFingerprint/dsa-1024 (0.00s)
        --- FAIL: Test_calcFingerprint/dsa-1024/SSHKeygen (0.00s)
            ssh_key_test.go:196:
                        Error Trace:    /src/gitea/models/asymkey/ssh_key_test.go:196
                        Error:          Received unexpected error:
                                        Unable to verify key content [result: /tmp/gitea_keytest1239408114 is not a public key file.
                                        ]
                        Test:           Test_calcFingerprint/dsa-1024/SSHKeygen
            ssh_key_test.go:197:
                        Error Trace:    /src/gitea/models/asymkey/ssh_key_test.go:197
                        Error:          Not equal:
                                        expected: "SHA256:fSIHQlpKMDsGPVAXI8BPYfRp+e2sfvSt1sMrPsFiXrc"
                                        actual  : ""

                                        Diff:
                                        --- Expected
                                        +++ Actual
                                        @@ -1 +1 @@
                                        -SHA256:fSIHQlpKMDsGPVAXI8BPYfRp+e2sfvSt1sMrPsFiXrc
                                        +
                        Test:           Test_calcFingerprint/dsa-1024/SSHKeygen
FAIL
```

Fix #31624