feat: add storage.total_limit_size support to splunk output

[geirra]

What this PR does / why we need it:

Adds storage.total_limit_size support to the Splunk output plugin, enabling
operators to limit the maximum on-disk chunk buffer size per Splunk output.

Follows the exact same pattern already implemented in 7 other output plugins
(Elasticsearch, OpenTelemetry, Syslog, Loki, Kafka, OpenSearch and HTTP).

Which issue(s) this PR fixes:

None

Does this PR introduced a user-facing change?

The Splunk output plugin now supports `totalLimitSize` to limit the maximum
number of filesystem chunks via `storage.total_limit_size`.

Additional documentation, usage docs, etc.:

- [Usage]: https://docs.fluentbit.io/manual/administration/buffering-and-storage#output-section-configuration

[Copilot]

Pull request overview

Adds storage.total_limit_size configuration support to the Fluent Bit Splunk output plugin in Fluent Operator, exposing it as totalLimitSize and wiring it through CRD schemas, Helm CRDs, and usage docs.

Changes:

• Added totalLimitSize to the Splunk output API type and render it into Fluent Bit params as storage.total_limit_size.
• Updated Splunk output plugin documentation to include the new field.
• Regenerated CRDs/manifests/Helm CRD artifacts to include the new schema property.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
manifests/setup/setup.yaml	Regenerated install manifest CRDs to include totalLimitSize under Splunk output schema.
docs/plugins/fluentbit/output/splunk.md	Documents the new totalLimitSize field for Splunk output.
config/crd/bases/fluentbit.fluent.io_outputs.yaml	Regenerated Output CRD schema to include totalLimitSize for Splunk.
config/crd/bases/fluentbit.fluent.io_clusteroutputs.yaml	Regenerated ClusterOutput CRD schema to include totalLimitSize for Splunk.
charts/fluent-operator/crds/fluentbit.fluent.io_outputs.yaml	Helm-packaged Output CRD updated with totalLimitSize.
charts/fluent-operator/crds/fluentbit.fluent.io_clusteroutputs.yaml	Helm-packaged ClusterOutput CRD updated with totalLimitSize.
charts/fluent-operator-fluent-bit-crds/templates/fluentbit.fluent.io_outputs.yaml	Fluent Bit CRD chart template updated with totalLimitSize.
charts/fluent-operator-fluent-bit-crds/templates/fluentbit.fluent.io_clusteroutputs.yaml	Fluent Bit ClusterOutput CRD chart template updated with totalLimitSize.
apis/fluentbit/v1alpha2/plugins/output/splunk_types.go	Adds TotalLimitSize to Splunk output and inserts storage.total_limit_size into generated params.
apis/fluentbit/v1alpha2/plugins/output/splunk_types_test.go	Adds unit test validating storage.total_limit_size is emitted from TotalLimitSize.