stable - Automated by PowerShell release prep

> **Note for reviewers:** This PR uses transitive dependency pinning (`transitive=true`, `versionLock=minor`). If this is the first time this pipeline has run on this branch, a large number of transitive dependencies may appear pinned. This is expected behavior.

Add changelog for 7.6.8 release

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#### AI description  (iteration 1)
#### PR Classification
Documentation update.

#### PR Summary
Adds changelog entry for the v7.6.8 release.
- `CHANGELOG/7.6.md`: Added a new `[7.6.8]` section noting a build/packaging update to .NET SDK 10.0.402, with a compare link to the previous release v7.6.7.
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…ure from PowerShell (#28242)

Backport "Remove the Update Notification feature from PowerShell (#28242)" from GitHub master branch.

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#### AI description  (iteration 1)
#### PR Classification
Feature removal/cleanup: this PR removes the Update Notification feature from PowerShell.

#### PR Summary
This PR deletes the update notification feature entirely, removing related code, resources, and tests.
- Deleted `src/Microsoft.PowerShell.ConsoleHost/host/msh/UpdatesNotification.cs`, eliminating the update-check logic.
- `ConsoleHost.cs` and `CommandLineParameterParser.cs` no longer invoke update-check or notification display logic.
- `ManagedEntranceStrings.resx` had update notification message strings removed.
- `ConsoleHost.Tests.ps1` updated to remove references to the `POWERSHELL_UPDATECHECK` environment variable in tests.
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…ild Task: Build definition ID 13420: Build...

Backport "Localized file check-in by OneLocBuild Task: Build definition ID 13420: Build ID 2770454 (#28227)" from GitHub master to release/v7.6.8.

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#### AI description  (iteration 1)
#### PR Classification
Localization update: adds translated resource strings for existing error messages introduced in previous code changes.

#### PR Summary
This PR adds new localized resource entries (OneLocBuild Task) across all supported languages to synchronize `.resx` files with newly added English-language strings.
- `HelpDisplayStrings.*.resx` files: added `ModuleNameTooLong` resource string for module name length validation errors.
- `TestJsonCmdletStrings.*.resx` files: added `UnresolvedJsonSchemaRef` resource string for unresolved JSON schema reference errors.
- Changes apply uniformly across `cs`, `de`, `es`, `fr`, `it`, `ja`, `ko`, `pl`, `pt-BR`, `ru`, `tr`, `zh-Hans`, and `zh-Hant` locales.
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…the Update Notification change

Update v7.6.8 changelog to include the Update Notification change

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#### AI description  (iteration 1)
#### PR Classification
Documentation update.

#### PR Summary
Updates the v7.6.8 changelog to document the removal of the Update Notification feature.
- `CHANGELOG/7.6.md`: Added entry under "General Cmdlet Updates and Fixes" noting removal of the Update Notification feature from PowerShell (#28242).
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