Bug 2334647

When using Fedora's Flatpak distribution of KeePassXC, the KeePassXC browser extensions fail to connect to KeePassXC, and instead force the KeePassXC window to open at seemingly random times.

This is because browsers need to run the `keepassxc-proxy` command, but Flatpaks only allow for a single binary entry point. To work around this, KeePassXC offers a `utils/keepassxc-flatpak-wrapper.sh` script that is designed to be used as the entry point for Flatpaks, which chooses whether to run `keepassxc` or `keepassxc-proxy`, depending on the command line arguments. Then, KeePassXC internally detects that it's running in a Flatpak, and configures the browser extension to call the main Flatpak entry point, assuming that this will run its `utils/keepassxc-flatpak-wrapper.sh` command.

But Fedora's distribution of KeePassXC just points to the main application binary `keepassxc` as the entry point, and does not expose `keepassxc-proxy`. So, the browser extensions run that, and it just does the same thing as if I clicked "KeePassXC" in the Applications menu, instead of silently connecting to the KeePassXC instance as intended.

In Flathub's distribution of KeePassXC, `utils/keepassxc-flatpak-wrapper.sh` is specified as the entry point, and browser integration works correctly.

Reproducible: Always

Steps to Reproduce:
1. In the KeePassXC settings, enable browser integration for Firefox.
2. Install the KeePassXC browser extension for Firefox.
Actual Results:  
The browser extension shows a red X badge on the extension button in the toolbar. Clicking the extension button shows an error message explaining that the connection failed, and offering a button to reconnect. Clicking the reconnect button says "Key exchange failed."

Additionally, opening the browser or switching back and forth between browser windows will sometimes cause the main KeepassXC window to open into the foreground.

Expected Results:  
The browser extension should automatically connect to KeePassXC, and be able to autofill forms.