Fix typos in e2e scenarios documentation

[coderabbitai]

Two typos were found in the e2e scenarios documentation:

• Line 85: "submittion" should be "submission"
• Line 85: "invald" should be "invalid"

References:

• Pull Request: Updated e2e scenarios #1077
• Comment: Updated e2e scenarios #1077 (comment)
• Requested by: @tisnik

File: docs/e2e_scenarios.md