fix: mysql tests error

[sunng87]

I hereby agree to the terms of the GreptimeDB CLA

What's changed and what's your intention?

Fixes compilation error on default branch.

Checklist

• I have written the necessary rustdoc comments.
• I have added the necessary unit tests and integration tests.

Refer to a related PR or issue link (optional)

[codecov]

Codecov Report

Merging #897 (09c8485) into develop (5dfc24e) will decrease coverage by 0.12%.
The diff coverage is 90.00%.

@@             Coverage Diff             @@
##           develop     #897      +/-   ##
===========================================
- Coverage    86.49%   86.37%   -0.12%     
===========================================
  Files          427      427              
  Lines        57279    57285       +6     
===========================================
- Hits         49541    49482      -59     
- Misses        7738     7803      +65     

Flag	Coverage Δ
rust	86.37% <90.00%> (-0.12%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
src/servers/src/tls.rs	99.34% <90.00%> (-0.66%)	⬇️
src/object-store/src/test_util.rs	0.00% <0.00%> (-100.00%)	⬇️
src/datanode/src/instance.rs	49.76% <0.00%> (-15.79%)	⬇️
tests-integration/src/test_util.rs	87.55% <0.00%> (-11.99%)	⬇️
src/meta-srv/src/error.rs	95.34% <0.00%> (+0.58%)	⬆️
src/meta-srv/src/service/heartbeat.rs	87.23% <0.00%> (+1.06%)	⬆️
src/servers/src/mysql/handler.rs	68.75% <0.00%> (+1.56%)	⬆️
src/meta-client/src/rpc/util.rs	77.77% <0.00%> (+5.55%)	⬆️

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

[evenyag]

LGTM

[killme2008]

LGTM