[Bug] Cannot upload JMC Agent probe templates after a failure

[andrewazores]

Jun 20, 2023 8:32:28 PM io.cryostat.core.log.Logger error
SEVERE: new_file.xml
Jun 20, 2023 8:32:28 PM io.cryostat.core.log.Logger error
SEVERE: HTTP 500: new_file.xml
io.vertx.ext.web.handler.HttpException: Internal Server Error
Caused by: io.cryostat.net.web.http.api.v2.ApiException: new_file.xml
	at io.cryostat.net.web.http.api.v2.ProbeTemplateUploadHandler.handle(ProbeTemplateUploadHandler.java:161)
	at io.cryostat.net.web.http.api.v2.AbstractV2RequestHandler.handle(AbstractV2RequestHandler.java:108)
	at io.cryostat.net.web.http.api.v2.AbstractV2RequestHandler.handle(AbstractV2RequestHandler.java:71)
	at io.vertx.ext.web.impl.BlockingHandlerDecorator.lambda$handle$0(BlockingHandlerDecorator.java:48)
	at io.vertx.core.impl.ContextBase.lambda$null$0(ContextBase.java:137)
	at io.vertx.core.impl.ContextInternal.dispatch(ContextInternal.java:264)
	at io.vertx.core.impl.ContextBase.lambda$executeBlocking$1(ContextBase.java:135)
	at io.vertx.core.impl.TaskQueue.run(TaskQueue.java:76)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
	at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
	at java.base/java.lang.Thread.run(Thread.java:833)
Caused by: java.nio.file.FileAlreadyExistsException: new_file.xml
	at io.cryostat.core.agent.LocalProbeTemplateService.addTemplate(LocalProbeTemplateService.java:98)
	at io.cryostat.net.web.http.api.v2.ProbeTemplateUploadHandler.handle(ProbeTemplateUploadHandler.java:136)
	... 11 more
Jun 20, 2023 8:32:28 PM org.slf4j.impl.JDK14LoggerAdapter fillCallerData
SEVERE: 10.89.1.31 - - [Tue, 20 Jun 2023 20:32:28 GMT] 11ms "POST /api/v2/probes/jmc-agent-probe.xml HTTP/1.1" 500 96 bytes "http://localhost:8181/events?agentTab=agent-template" "Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/113.0"

See #238 . After failing to upload a template once, a retry with the file corrected fails with the above. Once in this state it doesn't appear to be recoverable - all upload attempts will fail this way.