Send ClientVersionUpdatedEvent for each client state change, not only on version updates

See merge request briar/briar!1724

in order to avoid two splash screens from being shown.

This seems to be necessary. Without the location turned on, the hotspot does not start showing a p2p error.

We need to have those permissions before doing things like accessing the Bluetooth address. So we force-disable the Bluetooth plugin if the permission is not granted. The UI then forces the permission before allowing to enable the plugin.

For some reason SettingsActivity does not need to be exported for it to be launched from system app settings.

androidx.test.ext:junit needed to be upgraded because it somehow brought in an activity without exported attribute

Speed up BridgeTest by only retrying bridges that have failed

See merge request briar/briar!1732

Update bridges

See merge request !1731

Upgrade obfs4proxy to 0.0.14-tor1 and enable uTLS for meek-lite

See merge request briar/briar!1730

Update meek bridge

See merge request briar/briar!1729

Use uTLS with Chrome profile for Snowflake

See merge request briar/briar!1728

Add TestLanTcpPluginFactory

See merge request briar/briar!1723

This factory provides a LanTcpPlugin that can connect to its own
address, useful for testing.

Use mailbox main branch for integration tests

See merge request briar/briar!1721

Fix imports for null-safety annotations

See merge request briar/briar!1720

End-to-end integration tests for communication via mailbox

Closes #2343

See merge request briar/briar!1699

Re-show mailbox unpaired dialog after screen-rotation

Closes #2358

See merge request briar/briar!1718