[alxndrsn]

In stubbed pulldata() implementation, always return the empty string instead of the instance_id arg.

Closes #96

What has been done to verify that this works as intended?

• added a new test
• ran locally
• ran in ci

Why is this the best possible solution? Were any other approaches considered?

"" is the default response for pulldata() in Collect when the function fails, so probably a safer default here:

• https://github.com/getodk/collect/blob/a62438d64b7356c2c90f138543e486e69db157c2/collect_app/src/main/java/org/odk/collect/android/dynamicpreload/handler/ExternalDataHandlerPull.java#L91
• https://github.com/getodk/collect/blob/a62438d64b7356c2c90f138543e486e69db157c2/collect_app/src/main/java/org/odk/collect/android/dynamicpreload/handler/ExternalDataHandlerPull.java#L107
• https://github.com/getodk/collect/blob/a62438d64b7356c2c90f138543e486e69db157c2/collect_app/src/main/java/org/odk/collect/android/dynamicpreload/handler/ExternalDataHandlerPull.java#L111

and https://github.com/getodk/collect/blob/a62438d64b7356c2c90f138543e486e69db157c2/collect_app/src/main/java/org/odk/collect/android/dynamicpreload/handler/ExternalDataHandlerPull.java#L103 via https://github.com/getodk/collect/blob/a62438d64b7356c2c90f138543e486e69db157c2/collect_app/src/main/java/org/odk/collect/android/dynamicpreload/ExternalDataUtil.java#L353-L355

Are there any risks to merging this code? If so, what are they?

Might validate invalid forms?