Remove spaces between commas in CSVs

[lognaturel]

Closes #3110

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

Visual inspection and updating tests.

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

Trivial change with no alternatives.

How does this change affect users? Describe intentional changes to behavior and behavior that could have accidentally been affected by code changes. In other words, what are the regression risks?

There's a potential risk of breaking downstream integrations that didn't strip whitespace. Strictly speaking, the column headers have been node, start, etc with a prepended space. I think it's best to make this correction as soon as possible.

Do we need any specific form for testing your changes? If so, please attach one.

Any form with audit logging such as trackingChangesTestForm.xml.txt

Does this change require updates to documentation? If so, please file an issue here and include the link below.

getodk/xforms-spec#234

Before submitting this PR, please make sure you have:

• run ./gradlew checkAll and confirmed all checks still pass OR confirm CircleCI build passes and run ./gradlew connectedDebugAndroidTest locally.
• verified that any code or assets from external sources are properly credited in comments and/or in the about file.
• verified that any new UI elements use theme colors. UI Components Style guidelines