fix: Missing commits from hotfix branch (#17997)

* fix: merge conflict

* fix: restored missing set_gst_state_and_state_number function

* fix: style linting as per codacy

* fix: Fixes related to customer/lead merging

* fix: merge conflict

* fix: Fixes related to customer/lead merging

* fix: Assign isue/opportunity to user

* fix: Assign isue/opportunity to user

* fix: Replaced Invoice type by GST Category

* fix: merge conflict

* fix: merge conflict

* fix: test cases

* fix: test cases

erpnext/support/doctype/issue/issue.json

@@ -69,7 +69,8 @@
    "fieldtype": "Data",
    "in_global_search": 1,
    "label": "Subject",
-   "reqd": 1
+   "reqd": 1,
+   "in_standard_filter": 1
   },
   {
    "fieldname": "customer",
@@ -336,7 +337,7 @@
  ],
  "icon": "fa fa-ticket",
  "idx": 7,
- "modified": "2019-05-20 15:19:00.771333",
+ "modified": "2019-06-27 15:19:00.771333",
  "modified_by": "Administrator",
  "module": "Support",
  "name": "Issue",
@@ -361,4 +362,4 @@
  "timeline_field": "customer",
  "title_field": "subject",
  "track_seen": 1
-}
+}