Fix NPE in StreamsPipesTest.testBinaryText

 [INFO] Running org.nuxeo.ai.pipes.StreamsPipesTest
 2021-03-19 17:05:19,805 [stream/introspectionPool-00,in:0,inCheckpoint:0,out:0,lastRead:1616173519805,lastTimer:0,wm:0,loop:3,rebalance assigned] WARN  [StreamIntrospectionComputation] Instance elected to introspect Nuxeo Stream activity
 RuntimeStreamFeature: Deploying Nuxeo Stream using Kafka
 WorkManagerFeature: Deploying WorkManager using default implementation
 StorageConfiguration: Deploying JDBC using DatabaseH2
 StorageConfiguration: Deploying a DBS repository using mongodb
 2021-03-19 17:05:33,540 [main] WARN  [TransientStorageComponent] Missing configuration for default transient store, using in-memory
 2021-03-19 17:05:33,882 [main] ERROR [OSGiRuntimeService] Nuxeo Platform Started
 ======================================================================
 = Component Loading Warnings:
   * Missing configuration for default transient store, using in-memory
 ======================================================================
 = Component Loading Status: Pending: 0 / Missing: 1 / Unstarted: 0 / Total: 140
   * service:org.nuxeo.runtime.stream.service.managment.contrib references missing [target=org.nuxeo.ecm.core.management.CoreManagementComponent;point=probes, target=org.nuxeo.ecm.core.management.CoreManagementComponent;point=healthCheck]
 ======================================================================
 [ERROR] Tests run: 4, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 14.392 s <<< FAILURE! - in org.nuxeo.ai.pipes.StreamsPipesTest
 [ERROR] testBinaryText(org.nuxeo.ai.pipes.StreamsPipesTest)  Time elapsed: 5.354 s  <<< ERROR!
 java.lang.NullPointerException
 	at org.nuxeo.ai.pipes.StreamsPipesTest.testBinaryText(StreamsPipesTest.java:141)