feat(launcher): Add configurable CA bundle environment variables to launcher v2

[rahul810050]

What this PR does / why we need it

This PR introduces support for configuring which CA-related environment variables the v2 launcher sets when a user provides a custom CA bundle path.

Currently, launcher_v2 unconditionally sets:

• REQUESTS_CA_BUNDLE
• AWS_CA_BUNDLE
• SSL_CERT_FILE

whenever CaCertPath is provided.
This behavior is too strict for some environments that want finer control—e.g., cloud-specific setups, distroless containers, or Python environments that expect only a subset of these variables.

This feature allows users to configure exactly which environment variables should be set.

Which issue(s) this PR fixes

Fixes #12329

Description of changes

1. Added new field to LauncherV2Options:

CACertEnvVars []string

Users may now specify which CA-related environment variables should be set.

2. Added full plumbing of the new option through the launcher stack

Including:

• NewLauncherV2
• LauncherV2.Execute
• executeV2
• execute

3. Updated default behavior

If CACertEnvVars is nil or empty, the launcher preserves legacy behavior and sets the original 3 environment variables:

REQUESTS_CA_BUNDLE
AWS_CA_BUNDLE
SSL_CERT_FILE

This ensures full backward compatibility.

4. Updated unit tests

All calls to executeV2 now include the new argument, and tests verify that launcher execution behavior continues to work as expected.

No changes were made to end-to-end or integration tests.

Testing done

• Added/updated unit tests in launcher_v2_test.go
• Verified all backend unit tests pass:

cd backend
go test ./...

• Verified the component module tests pass:

ok   github.com/kubeflow/pipelines/backend/src/v2/component

End-to-end and API integration tests expectedly fail locally due to requiring a real Kubernetes cluster; this is normal and identical to upstream contributor experience.

Backward compatibility

Fully backward compatible.

• If users do not specify CACertEnvVars, the launcher behaves exactly as before.
• No existing workflows break.
• No user APIs changed.

Documentation

A short follow-up PR will update the docs in docs/backend/tls explaining how to configure CA env vars via LauncherV2Options.

[google-oss-prow]

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[google-oss-prow]

Hi @rahul810050. Thanks for your PR.

I'm waiting for a kubeflow member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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