Build scan IDs in investigation quick links section are null for the CI/CI experiment in 2.6 and later

[erichaagdev]

In 2.6, running:

./04-validate-remote-build-caching-ci-ci.sh -1 https://ge.solutions-team.gradle.com/s/mwvafqerztkvc -2 https://ge.solutions-team.gradle.com/s/5shtuqjzoxrtu

Results in the following investigation quick links section:

Investigation Quick Links
-------------------------
Task execution overview:         https://ge.solutions-team.gradle.com/s/null/performance/execution
Executed tasks timeline:         https://ge.solutions-team.gradle.com/s/null/timeline?outcome=success,failed&sort=longest
Avoided cacheable tasks:         https://ge.solutions-team.gradle.com/s/null/timeline?outcome=from-cache&sort=longest
Executed cacheable tasks:        https://ge.solutions-team.gradle.com/s/null/timeline?cacheability=cacheable,overlapping-outputs,validation-failure&outcome=success,failed&sort=longest
Executed non-cacheable tasks:    https://ge.solutions-team.gradle.com/s/null/timeline?cacheability=any-non-cacheable,not:overlapping-outputs,not:validation-failure&outcome=success,failed&sort=longest
Build caching statistics:        https://ge.solutions-team.gradle.com/s/null/performance/build-cache
Task inputs comparison:          https://ge.solutions-team.gradle.com/c/null/null/task-inputs?cacheability=cacheable,overlapping-outputs,validation-failure

Notice the build scan IDs in the URL are null. This does not happen in 2.5.1:

Investigation Quick Links
-------------------------
Task execution overview:         https://ge.solutions-team.gradle.com/s/5shtuqjzoxrtu/performance/execution
Executed tasks timeline:         https://ge.solutions-team.gradle.com/s/5shtuqjzoxrtu/timeline?outcome=success,failed&sort=longest
Avoided cacheable tasks:         https://ge.solutions-team.gradle.com/s/5shtuqjzoxrtu/timeline?outcome=from-cache&sort=longest
Executed cacheable tasks:        https://ge.solutions-team.gradle.com/s/5shtuqjzoxrtu/timeline?cacheability=cacheable,overlapping-outputs,validation-failure&outcome=success,failed&sort=longest
Executed non-cacheable tasks:    https://ge.solutions-team.gradle.com/s/5shtuqjzoxrtu/timeline?cacheability=any-non-cacheable,not:overlapping-outputs,not:validation-failure&outcome=success,failed&sort=longest
Build caching statistics:        https://ge.solutions-team.gradle.com/s/5shtuqjzoxrtu/performance/build-cache
Task inputs comparison:          https://ge.solutions-team.gradle.com/c/mwvafqerztkvc/5shtuqjzoxrtu/task-inputs?cacheability=cacheable,overlapping-outputs,validation-failure