fix: use Http2ClientStream.sendPing() again

[anthony-swirldslabs]

Description:
Removing our custom sendPing() implementation and restoring the calls to Helidon's Http2ClientStream.sendPing(). This is to avoid a potential (although never experienced yet) thread-race in the Helidon code due to the way we had to implement our custom sendPing(). This is now possible because Helidon fixed a bug in their sendPing() under helidon-io/helidon#11442 , and that fix is released in Helidon 4.4.1 to which we've upgraded just yesterday: #783

I've run the existing PbjGrpcStressTest that we used to validate the ping situation, and it passes w/o any issues.

Related issue(s):

Fixes #769

Notes for reviewer:
All tests should pass.

Checklist

• Documented (Code comments, README, etc.)
• Tested (unit, integration, etc.)

[github-actions]

JUnit Test Report

    81 files  ±0      81 suites  ±0   3m 12s ⏱️ -4s
 1 519 tests ±0   1 515 ✅ ±0   4 💤 ±0  0 ❌ ±0 
10 407 runs  ±0  10 379 ✅ ±0  28 💤 ±0  0 ❌ ±0 

Results for commit 7e0abe1. ± Comparison against base commit dc36e0b.

[github-actions]

Integration Test Report

    419 files  ±0      419 suites  ±0   26m 27s ⏱️ + 7m 39s
114 982 tests ±0  114 982 ✅ ±0  0 💤 ±0  0 ❌ ±0 
115 224 runs  ±0  115 224 ✅ ±0  0 💤 ±0  0 ❌ ±0 

Results for commit 7e0abe1. ± Comparison against base commit dc36e0b.

This pull request removes 3 and adds 3 tests. Note that renamed tests count towards both.

com.hedera.pbj.integration.test.ParserNeverWrapsTest ‑ [1] com.hedera.pbj.integration.test.ParserNeverWrapsTest$$Lambda/0x0000000093c63a10@160c4d33
com.hedera.pbj.integration.test.ParserNeverWrapsTest ‑ [2] com.hedera.pbj.integration.test.ParserNeverWrapsTest$$Lambda/0x0000000093c63c58@fe32439
com.hedera.pbj.integration.test.ParserNeverWrapsTest ‑ [3] com.hedera.pbj.integration.test.ParserNeverWrapsTest$$Lambda/0x0000000093c66000@55c832cb

com.hedera.pbj.integration.test.ParserNeverWrapsTest ‑ [1] com.hedera.pbj.integration.test.ParserNeverWrapsTest$$Lambda/0x0000000090b97d78@7bdca57b
com.hedera.pbj.integration.test.ParserNeverWrapsTest ‑ [2] com.hedera.pbj.integration.test.ParserNeverWrapsTest$$Lambda/0x0000000090b92000@4075a4e2
com.hedera.pbj.integration.test.ParserNeverWrapsTest ‑ [3] com.hedera.pbj.integration.test.ParserNeverWrapsTest$$Lambda/0x0000000090b92248@6550814f