Valid edit command rejected

[nus-se-bot]

Describe the bug
Valid edit command for editing Opening Hours is entered, but nothing happens and result display suggests that no fields are provided.

To Reproduce
Steps to reproduce the behavior:

1. Enter "edit 1 o/1200 to 1700" and click enter.
2. Error: Command is rejected with result display showing "At least one field to edit must be provided."

Expected behavior
When inputting "edit 1 o/1200 to 1700", it should be accepted and the first listing should change opening hours to "1200 to 1700".

Screenshots

Additional context
Add any other context about the problem here.

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Reported by: @yongxiang1095
Severity: Medium

_{[original: nus-cs2103-AY1819S2/pe-dry-run#869]}