Changed server URL documentation from "account" level to "organization" level (#67)

* Changed "server URL" from "account" level to "organization" level

The dashboard now does not have the account level server URL section in the "accounts" section, instead it is in the "organization" level. Updated docs to reflect that.

* Added screenshot for organization level server URL setting

Author: samudranb

server-url/setting-server-urls.mdx

@@ -24,11 +24,11 @@ Server URLs can be set at **4 levels** in Vapi:
 Here's a breakdown of where you can set server URLs in Vapi:
 
 <AccordionGroup>
-  <Accordion title="Account" icon="table-columns" iconType="solid">
-    You can set an account-wide server URL in the [account section](https://dashboard.vapi.ai/account) of your dashboard.
+  <Accordion title="Organization" icon="table-columns" iconType="solid">
+    You can set an organization-wide server URL in the [organization section](https://dashboard.vapi.ai/vapi-api) of your dashboard.
 
-    <Frame caption="Setting your account-wide server URL.">
-      <img src="/static/images/server-url/settings-server-urls/setting-account-server-url.png" />
+    <Frame caption="Setting your organization-wide server URL.">
+      <img src="/static/images/server-url/settings-server-urls/org-settings-server-urls.png" />
     </Frame>
 
     If no other server URL is set, Vapi will use this one.