Update submodules for v1.2

[matthew-white]

I'll use this branch to update the submodules for v1.2. I'm also committing a path change that follows from getodk/central-backend#331. @issa-tseng, I think this is the only change needed to central after the Backend refactor — is that right?

[matthew-white]

CircleCI is failing, but it should pass once I update the submodules before release.

[matthew-white]

This is what I see when I diff locally for the last commit:

diff --git a/client b/client
index cddb691..4f366fd 160000
--- a/client
+++ b/client
@@ -1 +1 @@
-Subproject commit cddb691e40e84aabff87b9d427e22a50282d6f99
+Subproject commit 4f366fd674d83b7f2f156822e5a8d2ceca563b32
diff --git a/server b/server
index a33bc6f..24d20de 160000
--- a/server
+++ b/server
@@ -1 +1 @@
-Subproject commit a33bc6fb3c34fe38894b0e9d0bb404f81da325e6
+Subproject commit 24d20de20fdf2e03b55e687542fbc0cae889a9ff