Fix the build error on CI

```log
/flutter_custom_tabs_android/android/src/main/kotlin/com/github/droibit/flutter/plugins/customtabs/core/options/PartialCustomTabsConfiguration.kt: (4, 38): Unresolved reference: DP
/flutter_custom_tabs_android/android/src/main/kotlin/com/github/droibit/flutter/plugins/customtabs/core/options/PartialCustomTabsConfiguration.kt: (40, 47): Unresolved reference: DP
```

flutter_custom_tabs_android/android/src/main/kotlin/com/github/droibit/flutter/plugins/customtabs/core/options/PartialCustomTabsConfiguration.kt

@@ -1,7 +1,6 @@
 package com.github.droibit.flutter.plugins.customtabs.core.options
 
 import androidx.annotation.Dimension
-import androidx.annotation.Dimension.DP
 import androidx.browser.customtabs.CustomTabsIntent.ActivityHeightResizeBehavior
 
 class PartialCustomTabsConfiguration(
@@ -37,7 +36,7 @@ class PartialCustomTabsConfiguration(
             return this
         }
 
-        fun setCornerRadius(@Dimension(unit = DP) cornerRadius: Int?): Builder {
+        fun setCornerRadius(@Dimension(unit = Dimension.DP) cornerRadius: Int?): Builder {
             this.cornerRadius = cornerRadius
             return this
         }