[BEAM-7060] Prefer inspect module over funcsigs

[udim]

cherrypick of #9562

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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	---		---	---

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[udim]

R: @robertwb

[udim]

CC: @markflyhigh

[udim]

closing - dupe of #9591