Remove the hardcoded "Reminder" text.

If one wants to show "Reminder" on the report, he must write it in the level's
name. It is better because "Reminder" before the level of the name may be
awkward.

account_credit_control/report/report_credit_control_summary.xml

@@ -17,7 +17,7 @@
           </div>
 
           <h2 id="policy_level">
-            <span>Reminder</span> <span t-field="o.current_policy_level.name"/>
+            <span t-field="o.current_policy_level.name"/>
           </h2>
 
           <p>Dear,</p>