fix(automation): add zIndex and withinPortal props to dropdown components for improved UI consistency (#5527)

# Description of Changes
Closes: #5525
Closes: #5242


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## Checklist

### General

- [X] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [X] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md)
(if applicable)
- [X] I have performed a self-review of my own code
- [X] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### Translations (if applicable)

- [ ] I ran
[`scripts/counter_translation.py`](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/docs/counter_translation.md)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [X] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md#6-testing)
for more details.

Signed-off-by: Balázs Szücs <[email protected]>

frontend/src/core/components/tools/compress/CompressSettings.tsx

@@ -5,6 +5,7 @@ import { useTranslation } from "react-i18next";
 import { CompressParameters } from "@app/hooks/tools/compress/useCompressParameters";
 import ButtonSelector from "@app/components/shared/ButtonSelector";
 import apiClient from "@app/services/apiClient";
+import { Z_INDEX_AUTOMATE_DROPDOWN } from "@app/styles/zIndex";
 
 interface CompressSettingsProps {
   parameters: CompressParameters;
@@ -96,6 +97,7 @@ const CompressSettings = ({ parameters, onParameterChange, disabled = false }: C
                 { value: 'MB', label: 'MB' }
               ]}
               style={{ width: '80px' }}
+              comboboxProps={{ withinPortal: true, zIndex: Z_INDEX_AUTOMATE_DROPDOWN }}
             />
           </div>
         </Stack>