fix failed integration cases

[ylwu-amzn]

Issue #, if available:

Description of changes:

Fix flaky integration test cases

Test

1. Start local cluster with security plugin and run ./gradlew integTest -Dtests.rest.cluster=localhost:9200 -Dtests.cluster=localhost:9200 -Dtests.clustername="docker-cluster" -Dhttps=true -Dsecurity=true -Duser=admin -Dpassword=admin
2. Start local cluster without security plugin and run ./gradlew integTest -Dtests.rest.cluster=localhost:9200 -Dtests.cluster=localhost:9200 -Dtests.clustername="docker-cluster" -Dhttps=false and ./gradlew integTest -Dtests.rest.cluster=localhost:9200 -Dtests.cluster=localhost:9200 -Dtests.clustername="docker-cluster"
3. ./gradlew build
4. ./gradlew integTest -PnumNodes=3
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[codecov]

Codecov Report

Merging #385 (c465e6a) into main (c0962ea) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##               main     #385   +/-   ##
=========================================
  Coverage     79.07%   79.07%           
  Complexity     2658     2658           
=========================================
  Files           247      247           
  Lines         11717    11717           
  Branches       1008     1008           
=========================================
  Hits           9265     9265           
  Misses         1971     1971           
  Partials        481      481           

Flag	Coverage Δ	Complexity Δ
cli	79.27% <ø> (ø)	0.00 <ø> (ø)

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[saratvemulapalli]

Had an offline chat with @ylwu-amzn .
We intentionally wanted to run these tests if the https flag is set from the arguments. (Refer to comments on original PR: #331 (comment))
We set this in build.gradle: https://github.com/opendistro-for-elasticsearch/anomaly-detection/blob/main/build.gradle#L168-L172
Probably as we discussed the cleaner way is to add another case of false to the build.gradle script instead of adding isHttps() check for all of tests.

[ylwu-amzn]

Exclude SecureADRestIT if https is false in case someone test with "-Dhttps=false"