fix(ux)!: when error messages are present, supress non-error messages

[ankush]

Problem: During network request handling we often print several messages to help users... however during the course of handling such requests a single frappe.throw usually means full rollback of everything that happened in the request. Hence previous messages make no sense.

Summary of change: if there are any messages with raise_exception then only show errors.

Minimal reproducible example:

def onload(self):
    frappe.msgprint("success")
    frappe.throw("failure")

This will show up as:

Another real example when serial no generation fails:

XP vibes.

After this change:

closes #15674

[codecov]

Codecov Report

Merging #16284 (55e2480) into develop (b2e1155) will decrease coverage by 3.05%.
The diff coverage is 85.71%.

❗ Current head 55e2480 differs from pull request most recent head f8673a0. Consider uploading reports for the commit f8673a0 to get more accurate results

@@             Coverage Diff             @@
##           develop   #16284      +/-   ##
===========================================
- Coverage    56.76%   53.71%   -3.06%     
===========================================
  Files          756      752       -4     
  Lines        66827    66482     -345     
  Branches      5696     5616      -80     
===========================================
- Hits         37936    35709    -2227     
- Misses       25449    26771    +1322     
- Partials      3442     4002     +560     

Flag	Coverage Δ
ui-tests	38.35% <85.71%> (-8.81%)	⬇️

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[ankush]

unrelated test failure in list view paging. Test helper function timed out.