fix: fail on empty markdown export (#3429)

* fix: fail on empty markdown export

Signed-off-by: Pragnya <prag1704@gmail.com>

* chore: format files

Signed-off-by: Pragnya <prag1704@gmail.com>

* test: cover markdown export stat failures

Signed-off-by: Pragnya <prag1704@gmail.com>

* refactor: move cli export helpers

Signed-off-by: Pragnya <prag1704@gmail.com>

* test: cover export utils split list

Signed-off-by: Pragnya <prag1704@gmail.com>

---------

Signed-off-by: Pragnya <prag1704@gmail.com>