fix: handle PermissionError for auto repeat email notifications

[ruchamahabal]

Backport of: #9404

Fix for:

• Handle PermissionError while attaching auto created recurring document in the Auto Repeat Notifcation email:

Traceback (most recent call last):
  File "/home/frappe/benches/bench-2019-12-20/apps/frappe/frappe/automation/doctype/autorepeat/autorepeat.py", line 138, in createdocuments
    self.sendnotification(newdoc)
  File "/home/frappe/benches/bench-2019-12-20/apps/frappe/frappe/automation/doctype/autorepeat/autorepeat.py", line 223, in sendnotification
    filename=newdoc.name, printformat=printformat)]
  File "/home/frappe/benches/bench-2019-12-20/apps/frappe/frappe/init.py", line 1405, in attachprint
    "fcontent": getprint(doctype, name, printformat=printformat, style=style, html=html, aspdf=True, doc=doc, noletterhead=noletterhead, password=password)
  File "/home/frappe/benches/bench-2019-12-20/apps/frappe/frappe/init.py", line 1379, in getprint
    html = buildpage("printview")
  File "/home/frappe/benches/bench-2019-12-20/apps/frappe/frappe/website/render.py", line 188, in buildpage
    context = getcontext(path)
  File "/home/frappe/benches/bench-2019-12-20/apps/frappe/frappe/website/context.py", line 28, in getcontext
    context = buildcontext(context)
  File "/home/frappe/benches/bench-2019-12-20/apps/frappe/frappe/website/context.py", line 98, in buildcontext
    updatecontrollercontext(context, context.controller)
  File "/home/frappe/benches/bench-2019-12-20/apps/frappe/frappe/website/context.py", line 48, in updatecontrollercontext
    ret = module.getcontext(context)
  File "/home/frappe/benches/bench-2019-12-20/apps/frappe/frappe/www/printview.py", line 42, in getcontext
    noletterhead=frappe.formdict.noletterhead),
  File "/home/frappe/benches/bench-2019-12-20/apps/frappe/frappe/www/printview.py", line 82, in getrenderedtemplate
    frappe.throw(("Not allowed to print draft documents"), frappe.PermissionError)
  File "/home/frappe/benches/bench-2019-12-20/apps/frappe/frappe/init.py", line 364, in throw
    msgprint(msg, raiseexception=exc, title=title, indicator='red')
  File "/home/frappe/benches/bench-2019-12-20/apps/frappe/frappe/init.py", line 350, in msgprint
    _raiseexception()
  File "/home/frappe/benches/bench-2019-12-20/apps/frappe/frappe/init.py", line 316, in raiseexception
    raise raise_exception(msg)
frappe.exceptions.PermissionError: Not allowed to print draft documents

• The mail:

• Added docs: docs: auto repeat notification mail permission issue erpnext_com#672

• Fixed a failing test