iOS: Make default build static again (take 2)

amends aa3d08ee86, which attempted to
revert the default change to -shared in 4c26b48633 but failed to take
into account an explicitly passed -shared argument, resulting in:

ERROR: Feature 'shared' was enabled, but the pre-condition
'!config.uikit && !config.integrity' failed.

Change-Id: Ide381624245e7c132a07e98c9107be7126dd488a
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@qt.io>
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

configure.json

@@ -462,7 +462,8 @@
     "features": {
         "shared": {
             "label": "Building shared libraries",
-            "condition": "!config.uikit && !config.integrity",
+            "autoDetect": "!config.uikit",
+            "condition": "!config.integrity",
             "output": [
                 "shared",
                 "publicFeature",