Make figures loaded from experiment db viewable in notebook (qiskit-c…

…ommunity#1321)

### Summary

Make figures loaded from experiment db viewable in jupyter notebook as
suggested in qiskit-community#436 .
### Details and comments

Some details that should be in this section include:

- Why this change was necessary
  To  make it more comfortable to use figures in jupyter notebook.
- What do users and developers need to know about this change
To display figures of experiment data that were loaded from experiment
db don't need to convert to SVG.

---------

Co-authored-by: Will Shanks <[email protected]>

docs/howtos/cloud_service.rst

@@ -59,13 +59,11 @@ experiment <https://quantum.ibm.com/experiments/9640736e-d797-4321-b063-d503f8e9
     service = ExperimentData.get_service_from_backend(backend)
     load_expdata = ExperimentData.load("9640736e-d797-4321-b063-d503f8e98571", service)
 
-To display the figure, which is serialized into a string, we need the
-``SVG`` library:
+Now we can display the figure from the loaded experiment data:
 
 .. jupyter-input::
 
-    from IPython.display import SVG
-    SVG(load_expdata.figure(0).figure)
+    load_expdata.figure(0)
 
 .. image:: ./experiment_cloud_service/t1_loaded.png
 

qiskit_experiments/framework/experiment_data.py

@@ -67,6 +67,7 @@
     ExperimentDataSaveFailed,
 )
 
+
 if TYPE_CHECKING:
     # There is a cyclical dependency here, but the name needs to exist for
     # Sphinx on Python 3.9+ to link type hints correctly.  The gating on
@@ -192,7 +193,7 @@ def _repr_svg_(self):
         if isinstance(self.figure, str):
             return self.figure
         if isinstance(self.figure, bytes):
-            return str(self.figure)
+            return self.figure.decode("utf-8")
         return None
 
 

releasenotes/notes/figure_return_SVG-4ad72fc8a3bee3cb.yaml

@@ -0,0 +1,4 @@
+---
+fixes:
+  - |
+    Figures loaded from the experiment service are now rendered correctly in Jupyter Notebook.