Remove support for updating the IPython banner

It's not required for now and newer versions of Jupyter work quite
differently.
Refs #21251

qt/python/mantidqt/widgets/ipythonconsole/widget.py

@@ -42,12 +42,8 @@ class InProcessIPythonConsole(RichIPythonWidget):
         """
         A constructor matching that of RichIPythonWidget
         :param args: Positional arguments passed directly to RichIPythonWidget
-        :param kwargs: Keyword arguments. The following are used by this
-        widget:
-          - banner_extra: An additinal string to append to the default banner
+        :param kwargs: Keyword arguments passed directly to RichIPythonWidget
         """
-        # remove our arguments
-        banner_extra = kwargs.pop("banner_extra", "")
         super(InProcessIPythonConsole, self).__init__(*args, **kwargs)
 
         # create an in-process kernel
@@ -60,10 +56,6 @@ class InProcessIPythonConsole(RichIPythonWidget):
         shell = kernel.shell
         shell.run_code = async_wrapper(shell.run_code, shell)
 
-        # custom banner
-        if banner_extra:
-            self.banner += "\n" + banner_extra
-
         # attach channels and start kenel
         kernel_client = kernel_manager.client()
         kernel_client.start_channels()

qt/python/mantidqt/widgets/test/test_ipythonconsole.py

@@ -33,11 +33,8 @@ class InProcessIPythonConsoleTest(unittest.TestCase):
         widget = InProcessIPythonConsole()
         self.assertTrue(hasattr(widget, "kernel_manager"))
         self.assertTrue(hasattr(widget, "kernel_client"))
+        self.assertTrue(len(widget.banner) > 0)
 
-    def test_banner_extra_updates_banner(self):
-        widget = InProcessIPythonConsole(banner_extra="foo")
-        self.assertTrue(widget.banner.endswith("foo"))
-        self.assertTrue(widget.banner.startswith("Python"))
 
 
 if __name__ == '__main__':