Allow setting the user agent programmatically #37792

Job	Run time
Attach pull request number	2s
CI Sanity Check	32s
Initial JDK 17 Build	11m 59s
Calculate Test Jobs	11s
JVM Tests - JDK 17	20m 0s
JVM Tests - JDK 21	21m 26s
JVM Tests - JDK 17 Windows	20m 45s
Devtools Tests - JDK ${{ matrix.java.name }}	0s
Maven Tests - JDK ${{ matrix.java.name }}	0s
Gradle Tests - JDK ${{ matrix.java.name }}	0s
Quickstarts Compilation - JDK 17	5m 12s
Native Tests - Virtual Thread - Main	3m 33s
Kubernetes Tests - JDK ${{ matrix.java.name }}	0s
Native Tests - Virtual Thread - Messaging	9m 29s
Native Tests - Data4	7m 3s
MicroProfile TCKs Tests	5m 29s
Native Tests - Security2	5m 4s
Native Tests - Security3	5m 35s
Native Tests - Cache	10m 0s
Native Tests - HTTP	14m 46s
Native Tests - Misc1	6m 3s
Native Tests - Misc4	5m 19s
Build report	23s
	2h 32m 51s

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