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## Type of change
- [ ] Feature
- [x] Bugfix
- [ ] Technical
- [ ] Other :
## Content
`RustMediaLoader` creates the "${cacheDir}/temp/media" dir only once at class creation. Unfortunately when clearing an app's cache this directory will be deleted and the app's process won't be killed, so subsequent usages of the same instance of `RustMediaLoader` will not work because `cacheDirectory` does not exists. This fix makes sure that such directory is always checked and created if needed.
## Motivation and context
Fixes https://github.com/vector-im/element-x-android/issues/1788
## Screenshots / GIFs
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## Tests
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## Tested devices
- [ ] Physical
- [ ] Emulator
- OS version(s):
## Checklist
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- [ ] Changes have been tested on an Android device or Android emulator with API 23
- [ ] UI change has been tested on both light and dark themes
- [ ] Accessibility has been taken into account. See https://github.com/vector-im/element-x-android/blob/develop/CONTRIBUTING.md#accessibility
- [ ] Pull request is based on the develop branch
- [ ] Pull request includes a new file under ./changelog.d. See https://github.com/vector-im/element-x-android/blob/develop/CONTRIBUTING.md#changelog
- [ ] Pull request includes screenshots or videos if containing UI changes
- [ ] Pull request includes a [sign off](https://matrix-org.github.io/synapse/latest/development/contributing_guide.html#sign-off)
- [ ] You've made a self review of your PR
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