[Backport 2.x] Bump BouncyCastle from jdk15on to jdk15to18

[willyborankin]

Backport 9856cb7 from #8247

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: FAILURE ❌
• URL: https://build.ci.opensearch.org/job/gradle-check/18665/
• CommitID: 949cc99
  Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green.
  Is the failure a flaky test unrelated to your change?

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: FAILURE ❌
• URL: https://build.ci.opensearch.org/job/gradle-check/18686/
• CommitID: 949cc99
  Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green.
  Is the failure a flaky test unrelated to your change?

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: UNSTABLE ❕
• TEST FAILURES:

      2 org.opensearch.search.SearchWeightedRoutingIT.testStrictWeightedRoutingWithCustomString
      2 org.opensearch.remotestore.SegmentReplicationUsingRemoteStoreIT.testPressureServiceStats

• URL: https://build.ci.opensearch.org/job/gradle-check/18696/
• CommitID: 949cc99
  Please review all flaky tests that succeeded after retry and create an issue if one does not already exist to track the flaky failure.

[codecov]

Codecov Report

Merging #8341 (949cc99) into 2.x (2dbe33f) will increase coverage by 0.13%.
The diff coverage is 57.23%.

@@             Coverage Diff              @@
##                2.x    #8341      +/-   ##
============================================
+ Coverage     70.54%   70.68%   +0.13%     
- Complexity    56776    56893     +117     
============================================
  Files          4706     4714       +8     
  Lines        269087   269637     +550     
  Branches      39773    39856      +83     
============================================
+ Hits         189836   190582     +746     
+ Misses        62886    62652     -234     
- Partials      16365    16403      +38     

Impacted Files	Coverage Δ
...va/org/opensearch/geometry/GeometryCollection.java	92.85% <0.00%> (-3.44%)	⬇️
...in/java/org/opensearch/wildfly/model/Employee.java	0.00% <ø> (ø)
...ildfly/transport/RestHighLevelClientActivator.java	0.00% <ø> (ø)
...transport/RestHighLevelClientEmployeeResource.java	0.00% <ø> (ø)
...wildfly/transport/RestHighLevelClientProducer.java	0.00% <ø> (ø)
...ly/transport/RestHighLevelJacksonJsonProvider.java	0.00% <ø> (ø)
...apshots/restore/RestoreSnapshotRequestBuilder.java	15.00% <0.00%> (-0.79%)	⬇️
...java/org/opensearch/index/fielddata/FieldData.java	70.48% <0.00%> (-3.11%)	⬇️
...rg/opensearch/index/translog/RemoteFsTranslog.java	70.39% <0.00%> (-2.45%)	⬇️
...dex/translog/transfer/TranslogTransferManager.java	78.45% <0.00%> (-1.33%)	⬇️
... and 30 more

... and 458 files with indirect coverage changes