Fix the string for incompatable OS version.

Should show "requires p" when the required sdk version > 27(O MR).

Bug: 73098235
Test: Tested on TestDPC
Change-Id: I05e8480c5532dd51215fc6ccf7f17cbebe491b2a

Author: yuemingw

app/src/main/java/com/afwsamples/testdpc/common/preference/DpcPreferenceHelper.java

@@ -220,8 +220,8 @@ public void disableIfConstraintsNotMet() {
      */
     private CharSequence findConstraintViolation() {
         if (getDeviceSdkInt() < mMinSdkVersion) {
-            // FIXME: Remove this special checking once O is out.
-            if (mMinSdkVersion >= 26) {
+            // FIXME: Remove this special checking once P is out.
+            if (mMinSdkVersion > 27) {
                 return mContext.getString(R.string.requires_preview_release);
             }
             return mContext.getString(R.string.requires_android_api_level, mMinSdkVersion);

app/src/main/res/values/strings.xml

@@ -95,7 +95,7 @@
     <!-- Reasons for disabling preferences -->
     <string name="requires_android_api_level">Requires API level
         <xliff:g id="api level">%d</xliff:g></string>
-    <string name="requires_preview_release">Requires the Android O preview release</string>
+    <string name="requires_preview_release">Requires the Android P preview release</string>
     <string name="requires">Requires\u0020</string>
     <string name="requires_delimiter">,\u0020</string>
     <string name="requires_or">\u0020or\u0020</string>