profiles: keepassxc: document new socket location

The KeePassXC browser extension looks for the KeePassXC socket at
`${RUNUSER}/app/org.keepassxc.KeePassXC`[1].

But `${RUNUSER}/app` seems to be blacklisted in disable-common.inc under the
flatpak section[2], so the KeePassXC extension cannot connect to it.

Fixes #5447.

[1] https://github.com/keepassxreboot/keepassxc/blob/6b1ab1a5edd66ac10706a2fb5af34ec9458a901d/src/browser/BrowserShared.cpp#L41
[2] https://github.com/netblue30/firejail/blob/b89ec818926b4bcd3a58bb4e2a67b68a8090ba1c/etc/inc/disable-common.inc#L667

etc/profile-a-l/cachy-browser.profile

@@ -23,6 +23,7 @@ whitelist /usr/share/cachy-browser
 # Note: Start KeePassXC before CachyBrowser and keep it open to allow communication between them.
 #whitelist ${RUNUSER}/kpxc_server
 #whitelist ${RUNUSER}/org.keepassxc.KeePassXC.BrowserServer
+#noblacklist ${RUNUSER}/app
 
 # Add the next line to your cachy-browser.local to enable private-bin (Arch Linux).
 #private-bin dbus-launch,dbus-send,cachy-browser,sh

etc/profile-a-l/floorp.profile

@@ -22,6 +22,7 @@ whitelist ${HOME}/.floorp
 # Note: Start KeePassXC before floorp and keep it open to allow communication between them.
 #whitelist ${RUNUSER}/kpxc_server
 #whitelist ${RUNUSER}/org.keepassxc.KeePassXC.BrowserServer
+#noblacklist ${RUNUSER}/app
 
 dbus-user filter
 dbus-user.own org.mozilla.floorp.*

etc/profile-a-l/librewolf.profile

@@ -22,6 +22,7 @@ whitelist ${HOME}/.librewolf
 # Note: Start KeePassXC before Librewolf and keep it open to allow communication between them.
 #whitelist ${RUNUSER}/kpxc_server
 #whitelist ${RUNUSER}/org.keepassxc.KeePassXC.BrowserServer
+#noblacklist ${RUNUSER}/app
 
 whitelist /usr/share/librewolf