Update mattermost-desktop module

[github-actions[bot]]

mattermost-desktop: Update mattermost-desktop-5.10.0-linux-x64.tar.gz to 5.10.1-rc.1 mattermost-desktop: Update mattermost-desktop-5.10.0-linux-arm64.tar.gz to 5.10.1-rc.1 mattermost-desktop: Update v5.10.0.tar.gz to 5.10.1-rc.1

🤖 This pull request was automatically generated by flathub-infra/flatpak-external-data-checker. Please open an issue if you have any questions or complaints. 🤖

[flathubbot]

Started test build 163334

[flathubbot]

Build 163334 successful To test this build, install it from the testing repository:

flatpak install --user https://dl.flathub.org/build-repo/146406/com.mattermost.Desktop.flatpakref

[github-actions[bot]]

🤖 This PR passed CI, and automerge-flathubbot-prs is true in flathub.json, so I'm merging it automatically. 🤖