/enroll page: Update copy (#42602)

- We use "BYO mobile" instead of "corporate mobile":
https://docs.google.com/document/d/1aVZ_eAiUjq1pdltR5ckwcbOXKB0DMzmboWZlegqJXDk/edit?tab=t.0
- Decided to just go with "mobile" because that's more familiar to end
users
- Context:
https://fleetdm.slack.com/archives/C03C41L5YEL/p1774377975564699

frontend/templates/enroll-ota.html

@@ -207,7 +207,7 @@
         </section>
         <section class="mobile-enroll-sidebar">
           <div class="qr-container">
-            <p>Trying to enroll your corporate mobile device?</p>
+            <p>Trying to enroll your mobile device?</p>
             <canvas class="qr-code"></canvas>
           </div>
         </section>
@@ -402,7 +402,7 @@
         </section>
         <section class="mobile-enroll-sidebar">
           <div class="qr-container">
-            <p>Trying to enroll your corporate mobile device?</p>
+            <p>Trying to enroll your mobile device?</p>
             <canvas class="qr-code"></canvas>
           </div>
         </section>