[Fix][Alert]Fix Webex Teams Alert Plugin Null Exception Error

[qingwli]

No description provided.

[codecov-commenter]

Codecov Report

Merging #13591 (9be8326) into dev (eaf2541) will decrease coverage by 0.01%.
The diff coverage is 0.00%.

❗ Current head 9be8326 differs from pull request most recent head f87f594. Consider uploading reports for the commit f87f594 to get more accurate results

@@             Coverage Diff              @@
##                dev   #13591      +/-   ##
============================================
- Coverage     39.47%   39.46%   -0.01%     
+ Complexity     4381     4380       -1     
============================================
  Files          1102     1102              
  Lines         41453    41453              
  Branches       4740     4738       -2     
============================================
- Hits          16362    16358       -4     
- Misses        23273    23275       +2     
- Partials       1818     1820       +2     

Impacted Files	Coverage Δ
...uler/plugin/alert/webexteams/WebexTeamsSender.java	76.38% <0.00%> (-1.39%)	⬇️
.../sqoop/parameter/sources/SourceMysqlParameter.java	71.42% <0.00%> (-3.58%)	⬇️
...r/plugin/task/sqoop/parameter/SqoopParameters.java	38.09% <0.00%> (-1.20%)	⬇️
...e/dolphinscheduler/remote/NettyRemotingClient.java	52.08% <0.00%> (-0.70%)	⬇️

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[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

66.7% Coverage
0.0% Duplication

[SbloodyS]

LGTM