Docs: change badges.svg example to pipeline.svg

What does this MR do?

Fix the example given on Badges section to something that we can see in badge preview

• Before:
  
• After:
  

Edit: actual change is to the new format (pipeline.svg)

Related issues

Author's checklist

• Apply the correct labels and milestone
• Crosslink the document from the higher-level index
• Crosslink the document from other subject-related docs
• Feature moving tiers? Make sure the change is also reflected in features.yml
• Correctly apply the product badges and tiers
• Port the MR to EE (or backport from CE): always recommended, required when the ee-compat-check job fails

Review checklist

• Your team's review (required)
• PM's review (recommended, but not a blocker)
• Technical writer's review (required)
• Merge the EE-MR first, CE-MR afterwards