SONAR-12798 Remove `Java` from validation message for settings of type 'regex pattern'

sonar-core/src/main/resources/org/sonar/l10n/core.properties

@@ -1044,7 +1044,7 @@ property.category.technicalDebt=Technical Debt
 property.error.notBoolean=Valid options are "true" and "false"
 property.error.notInteger=Only digits are allowed
 property.error.notFloat=Not a floating point number
-property.error.notRegexp=Not a valid Java regular expression
+property.error.notRegexp=Regular expression must be valid
 property.error.notInOptions=Not a valid option
 property.category.scm=SCM
 property.category.housekeeping=Housekeeping