fix: scim 2.0 patch ignore op casing (#9282)

# Which Problems Are Solved
- Some SCIM clients send "op" of a patch operation in PascalCase

# How the Problems Are Solved
- Well known "op" values of patch operations are matched
case-insensitive.

# Additional Context
Related to #8140

internal/api/scim/integration_test/testdata/users_update_test_full.json

@@ -3,7 +3,7 @@
   "Operations": [
     // add without path
     {
-      "op": "add",
+      "op": "Add", // with PascalCase operation type
       "value": {
         "emails":[
           {
@@ -17,7 +17,7 @@
     },
     // add complex attribute with path
     {
-      "op": "add",
+      "op": "add", // with camelCase operation type
       "path":  "name",
       "value": {
         "formatted": "added-formatted",
@@ -30,7 +30,7 @@
     },
     // add complex attribute value
     {
-      "op": "add",
+      "op": "ADD", // with UPPERCASE operation type
       "path": "name.middlename",
       "value": "added-middle-name-2"
     },