[BEAM-9811] Copy pom for all publishMavenJavaPublication tasks

[tweise]

Since the repository names are appended to the task names, we need to apply copyPom based on the task name prefix. This is follow-up for #11513

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Post-Commit Tests Status (on master branch)

Lang	SDK	Apex	Dataflow	Flink	Gearpump	Samza	Spark
Go		---	---		---	---
Java
Python		---			---	---
XLang	---	---	---		---	---

Pre-Commit Tests Status (on master branch)

---	Java	Python	Go	Website
Non-portable
Portable	---		---	---

See .test-infra/jenkins/README for trigger phrase, status and link of all Jenkins jobs.

[chamikaramj]

LGTM