[Hosts]Add learn more link to warning dialog (#39946)

## Summary of the Pull Request
Adds a *Learn more* link pointing
[here](https://aka.ms/PowerToysOverview_HostsFileEditor) (the same as in
the settings) to the warning dialog that shows up when Hosts File Editor
starts
## PR Checklist
- [x] **Closes:** #39859
- [ ] **Communication:** I've discussed this with core contributors
already. If work hasn't been agreed, this work might be rejected
- [ ] **Tests:** Added/updated and all pass
- [x] **Localization:** All end user facing strings can be localized
- [x] **Dev docs:** No need
- [x] **New binaries:** None
- [x] **Documentation updated:** No need
## Detailed Description of the Pull Request / Additional comments

![Image](https://github.com/user-attachments/assets/f26c4fc9-fc3f-45d1-9976-77295b524b97)
<!-- Describe how you validated the behavior. Add automated tests
wherever possible, but list manual validation steps taken as well -->
## Validation Steps Performed
Tested the UI manually

src/modules/Hosts/HostsUILib/Strings/en-us/Resources.resw

@@ -331,6 +331,9 @@
   <data name="WarningDialog_Title" xml:space="preserve">
     <value>Warning</value>
   </data>
+  <data name="WarningDialog_LearnMore" xml:space="preserve">
+    <value>Learn more</value>
+  </data>
   <data name="WindowAdminTitle" xml:space="preserve">
     <value>Administrator: Hosts File Editor</value>
     <comment>Title of the window when running as administrator. "Hosts File Editor" is the name of the utility. "Hosts" refers to the system hosts file, do not loc</comment>