fix(bil): fix saving plan options (#3790)

Author: bene2k1

console/billing/how-to/purchase-savings-plan.mdx

@@ -36,7 +36,7 @@ For more details about how Savings Plans work, how they are billed and which res
     <Message type="note">
       Currently, Scaleway only offers Savings Plans for compute resources.
     </Message>
-5. Select the duration of the plan. You can choose between 12, 24 and 36 months.
+5. Select the duration of the plan. You can choose between 12 and 36 months.
     <Message type="important">
       Keep in mind that once purchased, Savings Plans cannot be canceled or exchanged.
     </Message>