fix: speedup flag filtering in GraphQL API (#223)

Speed up filtering by flags in GraphQL endpoints by rewriting the search function to be able to compute faster on average.
Change it to exit each of the nested for loops quicker by not going through the entire iterator.

services/report.py

@@ -249,14 +249,17 @@ def sessions_with_specific_flags(
 
 
 def files_in_sessions(commit_report: Report, session_ids: List[int]) -> List[str]:
-    return [
-        file.name
-        for file in commit_report
-        if any(
-            [
-                any([session.id in session_ids for session in line.sessions])
-                for line in file
-                if line
-            ]
-        )
-    ]
+    files, session_ids = [], set(session_ids)
+    for file in commit_report:
+        found = False
+        for line in file:
+            if line:
+                for session in line.sessions:
+                    if session.id in session_ids:
+                        found = True
+                        break
+            if found:
+                break
+        if found:
+            files.append(file.name)
+    return files