chore: bump all use of Flux APIs to their latest version

[erikgb]

Closes

What changed?

All use of Flux APIs has been bumped to their latest version.

Why was this change made?

To keep up with the API evolution in Flux and avoid issues when API versions are removed.

How was this change implemented?

How did you validate the change?

Release notes

Documentation Changes

[Copilot]

Pull Request Overview

This PR updates all Flux API references to their latest stable versions, moving away from beta versions to improve compatibility and avoid deprecation issues.

• Updates source toolkit APIs from v1beta2 to v1
• Updates helm toolkit APIs from v2beta2 to v2
• Updates image automation and reflector APIs from v1beta2 to v1
• Updates notification controller APIs from v1beta2 to v1beta3

Reviewed Changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
website/docs/progressive-delivery/progressive-delivery-flagger-install.mdx	Updates source.toolkit.fluxcd.io API version in documentation examples
website/docs/open-source/getting-started/install-OSS.mdx	Updates helm.toolkit.fluxcd.io API version in documentation
website/docs/gitopssets/templating-from-generators.mdx	Updates source.toolkit.fluxcd.io API versions in GitOpsSets examples
website/docs/gitopssets/gitopssets-installation.mdx	Updates source.toolkit.fluxcd.io API version in installation docs
website/docs/gitops-templates/quickstart-templates.mdx	Updates source.toolkit.fluxcd.io API version in quickstart template
ui/pages/tests/Sources.test.tsx	Updates test data to reflect new API versions
ui/lib/tests/objects.test.ts	Updates test payloads with new API versions
ui/components/tests/ProviderDetail.test.tsx	Updates notification controller API versions in test data
tools/dev-resources/image-policy/*.yaml	Updates image.toolkit.fluxcd.io API versions from v1beta2 to v1
pkg/kube/kubehttp.go	Updates Go imports to use stable API versions and removes deprecated imports
core/server/sync_test.go	Updates Go imports for image automation and reflector controllers
core/server/suspend_test.go	Updates Go imports for image automation and reflector controllers
core/fluxsync/adapters.go	Updates Go imports and removes references to deprecated v1beta2 APIs

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