fix(rulesets): avoid false errors from ajv

This commit modifies the oasExample function so
that example fields are removed from the schema
to be used for validation.  This is needed because
the presence of an "example" field in a schema
confuses ajv in certain scenarios.
References:
- stoplightio#2081
- stoplightio#2140
- ajv-validator/ajv#1426

package.json

@@ -39,7 +39,8 @@
     "test.karma": "karma start",
     "prepare": "husky install",
     "prerelease": "patch-package",
-    "release": "yarn prerelease && yarn workspaces foreach run release"
+    "release": "yarn prerelease && yarn workspaces foreach run release",
+    "jest": "jest"
   },
   "workspaces": {
     "packages": [

packages/functions/src/schema/index.ts

@@ -69,7 +69,10 @@ export default createRulesetFunction<unknown, Options>(
       // let's ignore any $ref errors if schema fn is provided with already resolved content,
       // if our resolver fails to resolve them,
       // ajv is unlikely to do it either, since it won't have access to the whole document, but a small portion of it
-      if (!rule.resolved || !(ex instanceof MissingRefError)) {
+      // We specifically check that "rule" is truthy below because "rule" might be undefined/null if this
+      // code is called from testcases.
+      const ignoreError = rule?.resolved && ex instanceof MissingRefError;
+      if (!ignoreError) {
         results.push({
           message: ex.message,
           path,