Remove the check on number of enum class.

Now that we have more developers, we can have conflict because ot the number of exception. Let's hope we will not do the mistake...

tools/check/forbidden_strings_in_code.txt

@@ -159,9 +159,6 @@ Formatter\.formatShortFileSize===1
 # DISABLED
 # android\.text\.TextUtils
 
-### This is not a rule, but a warning: the number of "enum class" has changed. For Json classes, it is mandatory that they have `@JsonClass(generateAdapter = false)`. If the enum is not used as a Json class, change the value in file forbidden_strings_in_code.txt
-enum class===121
-
 ### Do not import temporary legacy classes
 import org.matrix.android.sdk.internal.legacy.riot===3
 import org.matrix.androidsdk.crypto.data===2