[backend] fix python injector missing callback route (#2230)

Co-authored-by: Romuald Lemesle <[email protected]>

openbas-api/src/main/java/io/openbas/rest/inject/InjectApi.java

@@ -109,10 +109,18 @@ public Inject injectExecutionReception(
     return injectRepository.save(inject);
   }
 
+  @Secured(ROLE_ADMIN)
+  @PostMapping(INJECT_URI + "/execution/callback/{injectId}")
+  public Inject injectExecutionCallback(
+      @PathVariable String injectId, @Valid @RequestBody InjectExecutionInput input) {
+    return injectExecutionCallback(null, injectId, input);
+  }
+
   @Secured(ROLE_ADMIN)
   @PostMapping(INJECT_URI + "/execution/{agentId}/callback/{injectId}")
   public Inject injectExecutionCallback(
-      @PathVariable String agentId,
+      @PathVariable
+          String agentId, // must allow null because http injector used also this method to work.
       @PathVariable String injectId,
       @Valid @RequestBody InjectExecutionInput input) {
     Inject inject = injectRepository.findById(injectId).orElseThrow(ElementNotFoundException::new);