[release/9.0-staging] Update dependencies from dotnet/icu (#123471)

This pull request updates the following dependencies

[marker]: <> (Begin:5e3f9b88-faad-436c-a580-ac009d20bb33)
## From https://github.com/dotnet/icu
- **Subscription**:
[5e3f9b88-faad-436c-a580-ac009d20bb33](https://maestro.dot.net/subscriptions?search=5e3f9b88-faad-436c-a580-ac009d20bb33)
- **Build**:
[20260128.1](https://dev.azure.com/dnceng/internal/_build/results?buildId=2889459)
([299108](https://maestro.dot.net/channel/3883/github:dotnet:icu/build/299108))
- **Date Produced**: January 28, 2026 11:44:17 AM UTC
- **Commit**:
[53915f585ca3dc5deff5c09c9492f7c5b7d925ca](dotnet/icu@53915f5)
- **Branch**:
[dotnet/release/9.0](https://github.com/dotnet/icu/tree/dotnet/release/9.0)

[DependencyUpdate]: <> (Begin)

- **Dependency Updates**:
  - From [9.0.0-rtm.25627.1 to 9.0.0-rtm.26078.1][5]
     - Microsoft.NETCore.Runtime.ICU.Transport

[5]: dotnet/icu@cda39b5...53915f5

[DependencyUpdate]: <> (End)


[marker]: <> (End:5e3f9b88-faad-436c-a580-ac009d20bb33)

---------

Co-authored-by: dotnet-maestro[bot] <dotnet-maestro[bot]@users.noreply.github.com>
Co-authored-by: Steve Pfister <steveisok@users.noreply.github.com>

Author: dotnet-maestro[bot]

NuGet.config

@@ -9,7 +9,6 @@
     <clear />
     <!--Begin: Package sources managed by Dependency Flow automation. Do not edit the sources below.-->
     <!--  Begin: Package sources from dotnet-emsdk -->
-    <add key="darc-pub-dotnet-emsdk-b9d2b36" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/darc-pub-dotnet-emsdk-b9d2b36b/nuget/v3/index.json" />
     <!--  End: Package sources from dotnet-emsdk -->
     <!--  Begin: Package sources from dotnet-sdk -->
     <!--  End: Package sources from dotnet-sdk -->

eng/Version.Details.xml

@@ -1,8 +1,8 @@
 <Dependencies>
   <ProductDependencies>
-    <Dependency Name="Microsoft.NETCore.Runtime.ICU.Transport" Version="9.0.0-rtm.25627.1">
+    <Dependency Name="Microsoft.NETCore.Runtime.ICU.Transport" Version="9.0.0-rtm.26078.1">
       <Uri>https://github.com/dotnet/icu</Uri>
-      <Sha>cda39b50d316241f6c9dea44ed241a83aaccdfac</Sha>
+      <Sha>53915f585ca3dc5deff5c09c9492f7c5b7d925ca</Sha>
     </Dependency>
     <Dependency Name="System.Net.MsQuic.Transport" Version="9.0.0-alpha.1.24167.3">
       <Uri>https://github.com/dotnet/msquic</Uri>

eng/Versions.props

@@ -227,7 +227,7 @@
     <!-- ILCompiler -->
     <MicrosoftDotNetILCompilerVersion>9.0.0-rtm.24511.16</MicrosoftDotNetILCompilerVersion>
     <!-- ICU -->
-    <MicrosoftNETCoreRuntimeICUTransportVersion>9.0.0-rtm.25627.1</MicrosoftNETCoreRuntimeICUTransportVersion>
+    <MicrosoftNETCoreRuntimeICUTransportVersion>9.0.0-rtm.26078.1</MicrosoftNETCoreRuntimeICUTransportVersion>
     <MicrosoftNETCoreRuntimeICUTransportVersion>9.0.0-rtm.24466.4</MicrosoftNETCoreRuntimeICUTransportVersion>
     <!-- MsQuic -->
     <MicrosoftNativeQuicMsQuicSchannelVersion>2.4.8</MicrosoftNativeQuicMsQuicSchannelVersion>