refactor(prepared-report): Do not serialize JSON serialized filters

Prepared report filters were being JSON serialized twice.
There isn't any apparent need to do this. So don't do it.

frappe/core/doctype/prepared_report/prepared_report.js

@@ -15,7 +15,7 @@ frappe.ui.form.on('Prepared Report', {
 			<tbody></tbody>
 		</table>`);
 
-		const filters = JSON.parse(JSON.parse(frm.doc.filters));
+		const filters = JSON.parse(frm.doc.filters);
 
 		Object.keys(filters).forEach(key => {
 			const filter_row = $(`<tr>

frappe/core/doctype/prepared_report/prepared_report.py

@@ -35,7 +35,7 @@ class PreparedReport(Document):
 
 def run_background(instance):
 	report = frappe.get_doc("Report", instance.ref_report_doctype)
-	result = generate_report_result(report, filters=json.loads(instance.filters), user=instance.owner)
+	result = generate_report_result(report, filters=instance.filters, user=instance.owner)
 	create_json_gz_file(result['result'], 'Prepared Report', instance.name)
 
 	instance.status = "Completed"

frappe/desk/query_report.py

@@ -100,7 +100,9 @@ def background_enqueue_run(report_name, filters=None, user=None):
 		frappe.get_doc({
 			"doctype": "Prepared Report",
 			"report_name": report_name,
-			"filters": json.dumps(filters),
+			# This looks like an insanity but, without this it'd be very hard to find Prepared Reports matvhing given condition
+			# We're ensuring that spacing is consistent. e.g. JS seems to put no spaces after ":", Python on the other hand does.
+			"filters": json.dumps(json.loads(filters)),
 			"ref_report_doctype": report_name,
 			"report_type": report.report_type,
 			"query": report.query,