kcms: remove mediacenter from formfactors

KCMs in this repo have `mediacenter` in their form factor lists, which will cause them to show up on Plasma Bigscreen. This MR fixes that.

**Code changes:**
- [x] In `info`, `mobileshell`, `time`, `virtualkeyboard`, and `waydroidintegration`, remove mediacenter from form factors

kcms/info/kcm_mobile_info.json

@@ -39,9 +39,7 @@
         "Description[zh_CN]": "软件版本",
         "Description[zh_TW]": "軟體版本",
         "FormFactors": [
-            "handset",
-            "tablet",
-            "mediacenter"
+            "handset", "tablet"
         ],
         "Icon": "dialog-information",
         "Name": "Information",

kcms/mobileshell/kcm_mobileshell.json

@@ -85,8 +85,7 @@
         "FormFactors": [
             "desktop",
             "handset",
-            "tablet",
-            "mediacenter"
+            "tablet"
         ],
         "Icon": "preferences-desktop-plasma",
         "License": "GPL",

kcms/time/kcm_mobile_time.json

@@ -40,8 +40,7 @@
         "Description[zh_TW]": "時區、日期顯示",
         "FormFactors": [
             "handset",
-            "tablet",
-            "mediacenter"
+            "tablet"
         ],
         "Icon": "preferences-system-time",
         "Name": "Time and Date",

kcms/waydroidintegration/kcm_waydroidintegration.json

@@ -50,8 +50,7 @@
         "FormFactors": [
             "desktop",
             "handset",
-            "tablet",
-            "mediacenter"
+            "tablet"
         ],
         "Icon": "folder-android-symbolic",
         "License": "GPL",