restore text of Invoke button (#4606)

## What type of PR is this? (check all applicable)

- [ ] Refactor
- [ ] Feature
- [ ] Bug Fix
- [ ] Optimization
- [ ] Documentation Update
- [ ] Community Node Submission


## Have you discussed this change with the InvokeAI team?
- [ ] Yes
- [ ] No, because:

      
## Have you updated all relevant documentation?
- [ ] Yes
- [ ] No


## Description


## Related Tickets & Documents

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- Related Issue #
- Closes #

## QA Instructions, Screenshots, Recordings

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## Added/updated tests?

- [ ] Yes
- [ ] No : _please replace this line with details on why tests
      have not been included_

## [optional] Are there any post deployment tasks we need to perform?

invokeai/frontend/web/src/features/queue/components/QueueBackButton.tsx

@@ -1,6 +1,5 @@
 import { memo } from 'react';
 import { useTranslation } from 'react-i18next';
-import { FaPlus } from 'react-icons/fa';
 import { useQueueBack } from '../hooks/useQueueBack';
 import EnqueueButtonTooltip from './QueueButtonTooltip';
 import QueueButton from './common/QueueButton';
@@ -18,12 +17,11 @@ const QueueBackButton = ({ asIconButton, sx }: Props) => {
     <QueueButton
       asIconButton={asIconButton}
       colorScheme="accent"
-      label={t('queue.queueBack')}
+      label={t('parameters.invoke.invoke')}
       isDisabled={isDisabled}
       isLoading={isLoading}
       onClick={queueBack}
       tooltip={<EnqueueButtonTooltip />}
-      icon={<FaPlus />}
       sx={sx}
     />
   );

invokeai/frontend/web/src/features/queue/components/common/QueueButton.tsx

@@ -6,7 +6,7 @@ import { ReactElement, ReactNode, memo } from 'react';
 type Props = {
   label: string;
   tooltip: ReactNode;
-  icon: ReactElement;
+  icon?: ReactElement;
   onClick?: () => void;
   isDisabled?: boolean;
   colorScheme: ThemeTypings['colorSchemes'];