fix(k8s): fix job log modal overflow (#7256)

adding a couple flex fills to ensure that the model fills the screen
without overflowing. now the log output scrolls when it overflows and
the rest of the modal stays static.

Fixes spinnaker/spinnaker#4649

app/scripts/modules/core/src/manifest/stage/JobManifestPodLogs.tsx

@@ -85,11 +85,11 @@ export class JobManifestPodLogs extends React.Component<IJobManifestPodLogsProps
           <a onClick={this.onClick} className="clickable">
             {this.props.linkName}
           </a>
-          <Modal show={showModal} onHide={this.close} dialogClassName="modal-lg modal-fullscreen">
+          <Modal show={showModal} onHide={this.close} dialogClassName="modal-lg modal-fullscreen flex-fill">
             <Modal.Header closeButton={true}>
               <Modal.Title>Console Output: {this.podName()} </Modal.Title>
             </Modal.Header>
-            <Modal.Body>
+            <Modal.Body className="flex-fill">
               {containerLogs.length && (
                 <>
                   <ul className="tabs-basic console-output-tabs">
@@ -105,7 +105,7 @@ export class JobManifestPodLogs extends React.Component<IJobManifestPodLogsProps
                       </li>
                     ))}
                   </ul>
-                  <pre className="body-small">{selectedContainerLog.output}</pre>
+                  <pre className="body-small flex-fill">{selectedContainerLog.output}</pre>
                 </>
               )}
               {errorMessage && <pre className="body-small">{errorMessage}</pre>}