Update migration script to not remove schedule from functions

[stnguyen90]

What does this PR do?

The schedule attribute was not removed from the functions collection so we shouldn't delete it.

Test Plan

Running migration after upgrading from 1.3.8:

functions table:

Migrating after running 1.4.0 migration:

functions table:

Related PRs and Issues

• 🐛 Bug Report: Invalid document structure: Unknown attribute: "schedule" #6151

Checklist

• Have you read the Contributing Guidelines on issues?
• If the PR includes a change to an API's metadata (desc, label, params, etc.), does it also include updated API specs and example docs?

[christyjacob4]

did we make sure to include it in the collections.php file ?

[stnguyen90]

Ya, it's already in there:

appwrite/app/config/collections.php

Lines 1980 to 1990 in 458dd8c

	[
	'$id' => ID::custom('schedule'),
	'type' => Database::VAR_STRING,
	'format' => '',
	'size' => 128,
	'signed' => true,
	'required' => false,
	'default' => null,
	'array' => false,
	'filters' => [],
	],