[CmdPal] Extension string updates (#43269)

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## Summary of the Pull Request

Feedback from the design team:
- Reduce any redundant or long text strings for better readability and
localization
- `Verb + noun` for most extensions
- Sentence casing according to the Windows Writing Guidelines


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## PR Checklist

- [ ] Closes: #xxx
- [ ] **Communication:** I've discussed this with core contributors
already. If the work hasn't been agreed, this work might be rejected
- [ ] **Tests:** Added/updated and all pass
- [ ] **Localization:** All end-user-facing strings can be localized
- [ ] **Dev docs:** Added/updated
- [ ] **New binaries:** Added on the required places
- [ ] [JSON for
signing](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ESRPSigning_core.json)
for new binaries
- [ ] [WXS for
installer](https://github.com/microsoft/PowerToys/blob/main/installer/PowerToysSetup/Product.wxs)
for new binaries and localization folder
- [ ] [YML for CI
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ci/templates/build-powertoys-steps.yml)
for new test projects
- [ ] [YML for signed
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/release.yml)
- [ ] **Documentation updated:** If checked, please file a pull request
on [our docs
repo](https://github.com/MicrosoftDocs/windows-uwp/tree/docs/hub/powertoys)
and link it here: #xxx

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## Detailed Description of the Pull Request / Additional comments

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Co-authored-by: Michael Jolley <mike@baldbeardedbuilder.com>
Co-authored-by: Jiří Polášek <me@jiripolasek.com>

src/modules/cmdpal/Tests/Microsoft.CmdPal.Ext.System.UnitTests/QueryTests.cs

@@ -25,7 +25,7 @@ public class QueryTests : CommandPaletteUnitTestBase
     [DataRow("hibernate", "Hibernate")]
     [DataRow("open recycle", "Open Recycle Bin")]
     [DataRow("empty recycle", "Empty Recycle Bin")]
-    [DataRow("uefi", "UEFI Firmware Settings")]
+    [DataRow("uefi", "UEFI firmware settings")]
     public void TopLevelPageQueryTest(string input, string matchedTitle)
     {
         var settings = new Settings();
@@ -143,6 +143,6 @@ public class QueryTests : CommandPaletteUnitTestBase
         Assert.IsNotNull(result);
         var firstItem = result.FirstOrDefault();
         var firstItemIsUefiCommand = firstItem?.Title.Contains("UEFI", StringComparison.OrdinalIgnoreCase) ?? false;
-        Assert.AreEqual(hasCommand, firstItemIsUefiCommand, $"Expected to match (or not match) 'UEFI Firmware Settings' but got '{firstItem?.Title}'");
+        Assert.AreEqual(hasCommand, firstItemIsUefiCommand, $"Expected to match (or not match) 'UEFI firmware settings' but got '{firstItem?.Title}'");
     }
 }