Update hush-payment-gateway.php

Storing price as option and using stored price when CoinGecko returns no price or errors.

hush-payment-gateway.php

@@ -77,7 +77,7 @@ function get_hush_price() {
     $request = wp_remote_get('https://api.coingecko.com/api/v3/simple/price?ids=hush&vs_currencies=btc%2Cusd%2Ceur%2Ceth%2Cgbp%2Ccny%2Cjpy%2Cidr%2Crub%2Ccad%2Csgd%2Cchf%2Cinr%2Caud%2Cinr%2Ckrw%2Cthb%2Cnzd%2Czar%2Cvef%2Cxau%2Cxag%2Cvnd%2Csar%2Ctwd%2Caed%2Cars%2Cbdt%2Cbhd%2Cbmd%2Cbrl%2Cclp%2Cczk%2Cdkk%2Chuf%2Cils%2Ckwd%2Clkr%2Cpkr%2Cnok%2Ctry%2Csek%2Cmxn%2Cuah%2Chkd&include_market_cap=true&include_24hr_vol=true&include_24hr_change=true');
             
     if(is_wp_error($request)){
-        return false;
+        return get_option('hushPriceCached');
     }
 
     $body = wp_remote_retrieve_body($request);
@@ -86,14 +86,15 @@ function get_hush_price() {
     if(!empty($data)){
         $hushPrice = $data['hush']['usd'];
         if(is_numeric($hushPrice)){
+            update_option('hushPriceCached',sanitize_text_field($hushPrice));
             return $hushPrice;
         }
         else{
-            return false;
+            return get_option('hushPriceCached');
         }
     }            
     else{
-        return false;
+        return get_option('hushPriceCached');
     }
 }