Remove obsolete .snyk ignore entries after go-toolset 1.26.4 bump

Summary

PR #3347 bumps the registry.access.redhat.com/ubi9/go-toolset base image tag from 1.26.3 to 1.26.4-1783442369 in Dockerfile, images/Dockerfile.e2e, and images/Dockerfile.konflux.

The repo's .snyk file contains three ignore entries whose stated removal condition ("Remove when CI runs Go >= 1.26.4.") is now satisfied by this change:

• SNYK-GOLANG-STDNETTEXTPROTO-17135843
• SNYK-GOLANG-STDMIME-17135844
• SNYK-GOLANG-STDCRYPTOX509-17135840

Required change

Once the updated go-toolset (Go >= 1.26.4) image is confirmed running in CI builds, remove these three ignore blocks from the .snyk file at the repo root (each currently has an expires: 2026-08-01T00:00:00.000Z reason tied to the Go 1.26.3 -> 1.26.4 requirement).

Affected files

• .snyk

Acceptance criteria

• Confirm CI builder image is running Go >= 1.26.4.
• Remove the three obsolete ignore entries listed above from .snyk.
• Confirm snyk test no longer needs to suppress these advisories (i.e., underlying stdlib fix is present).

References

• PR: https://github.com/openshift/rosa/pull/3347
• Requested by: @amandahla