[BEAM-10234] Fix error message for missing licenses.

[ibzib]

I also yapf'd it while I was at it.

R: @udim

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Post-Commit Tests Status (on master branch)

Lang	SDK	Apex	Dataflow	Flink	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.

[ibzib]

Run PythonLint PreCommit

[ibzib]

Noting that PythonDocker failed, but at least it prints the error properly now :)