bugfix: fix the naming server node having a term of 0

[ggbocoder]

• I have registered the PR changes.

Ⅰ. Describe what this PR did

Ⅱ. Does this pull request fix one issue?

Ⅲ. Why don't you add test cases (unit test/integration test)?

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

[codecov]

Codecov Report

Attention: Patch coverage is 68.75000% with 5 lines in your changes missing coverage. Please review.

Project coverage is 52.16%. Comparing base (64035c5) to head (a4a741f).
Report is 1 commits behind head on 2.x.

Files	Patch %	Lines
...ache/seata/namingserver/manager/NamingManager.java	84.61%	0 Missing and 2 partials ⚠️
.../namingserver/NamingserverRegistryServiceImpl.java	0.00%	1 Missing ⚠️
...eata/namingserver/controller/NamingController.java	0.00%	1 Missing ⚠️
.../src/main/java/org/apache/seata/server/Server.java	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##                2.x    #6778   +/-   ##
=========================================
  Coverage     52.15%   52.16%           
- Complexity     6294     6295    +1     
=========================================
  Files          1064     1064           
  Lines         37215    37214    -1     
  Branches       4417     4417           
=========================================
+ Hits          19411    19413    +2     
  Misses        15883    15883           
+ Partials       1921     1918    -3     

Files	Coverage Δ
...eata/namingserver/controller/HealthController.java	50.00% <ø> (ø)
.../namingserver/NamingserverRegistryServiceImpl.java	0.00% <0.00%> (ø)
...eata/namingserver/controller/NamingController.java	38.88% <0.00%> (ø)
.../src/main/java/org/apache/seata/server/Server.java	48.38% <0.00%> (-0.80%)	⬇️
...ache/seata/namingserver/manager/NamingManager.java	65.56% <84.61%> (-0.33%)	⬇️

... and 3 files with indirect coverage changes

[funky-eyes]

LGTM