Clean up ServiceType property usage for JSON based plugins

Task: https://phabricator.kde.org/T14483

events/x11/krfb_events_x11.json

@@ -60,9 +60,6 @@
         "Name[x-test]": "xxX11 Event handler for KRfbxx",
         "Name[zh_CN]": "X11 KRfb 事件处理器",
         "Name[zh_TW]": "KRfb 的 X11 事件處理器",
-        "ServiceTypes": [
-            "krfb/events"
-        ],
         "Version": "0.1",
         "Website": "http://www.kde.org"
     }

events/xdp/krfb_events_xdp.json

@@ -60,9 +60,6 @@
         "Name[x-test]": "xxXdg-desktop-portal Event handler for KRfbxx",
         "Name[zh_CN]": "xdg-desktop-portal KRfb 事件处理器",
         "Name[zh_TW]": "KRfb 的 Xdg-desktop-portal 事件處理器",
-        "ServiceTypes": [
-            "krfb/events"
-        ],
         "Version": "0.1",
         "Website": "http://www.kde.org"
     }

framebuffers/pipewire/krfb_framebuffer_pw.json

@@ -64,9 +64,6 @@
         "Name[x-test]": "xxPipeWire Framebuffer for KRfbxx",
         "Name[zh_CN]": "KRfb 的 PipeWire 帧缓冲机制",
         "Name[zh_TW]": "KRfb 的 PipeWire Framebuffer",
-        "ServiceTypes": [
-            "krfb/framebuffer"
-        ],
         "Version": "0.1",
         "Website": "http://www.kde.org"
     }

framebuffers/qt/krfb_framebuffer_qt.json

@@ -75,9 +75,6 @@
         "Name[x-test]": "xxQt Framebuffer for KRfbxx",
         "Name[zh_CN]": "KRfb 的 Qt 帧缓冲",
         "Name[zh_TW]": "Krfb 的 Qt Framebuffer",
-        "ServiceTypes": [
-            "krfb/framebuffer"
-        ],
         "Version": "0.1",
         "Website": "https://www.kde.org"
     }

framebuffers/xcb/krfb_framebuffer_xcb.json

@@ -75,9 +75,6 @@
         "Name[x-test]": "xxX11 Framebuffer for KRfbxx",
         "Name[zh_CN]": "XRfb 的 X11 帧缓冲",
         "Name[zh_TW]": "KRfb 的 X11 Framebuffer",
-        "ServiceTypes": [
-            "krfb/framebuffer"
-        ],
         "Version": "0.1",
         "Website": "https://www.kde.org"
     }