ci/lava: Retry when data fetching log RPC call is corrupted

Rarely the jobs.logs RPC call can return corrupted data, such as
mal-formed YAML data. As this is expected and very rare to occur, let's
retry this RPC call several times to give it a chance to fix itself.

Retrying would not swallow the log lines since we keep track of how many
log lines each job has.

Signed-off-by: Guilherme Gallo <guilherme.gallo@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15938>

.gitlab-ci/lava/exceptions.py

@@ -14,4 +14,8 @@ class MesaCITimeoutError(MesaCIException):
 class MesaCIRetryError(MesaCIException):
     def __init__(self, *args, retry_count: int) -> None:
         super().__init__(*args)
-        self.retry_count = retry_count
+        self.retry_count = retry_count
+
+
+class MesaCIParseException(MesaCIException):
+    pass