fix: correct validation to be aligned with rules

Author: armano2

@commitlint/prompt/src/library/get-forced-case-fn.test.ts

@@ -33,11 +33,11 @@ test('should not apply', () => {
 
 test('should throw error on invalid casing', () => {
 	expect(() =>
-		getForcedCaseFn(['name', [RuleConfigSeverity.Warning, 'always']])
+		getForcedCaseFn(['name', [RuleConfigSeverity.Warning, 'always']])('')
 	).toThrow('Unknown target case "undefined"');
 
 	expect(() =>
-		getForcedCaseFn(['name', [RuleConfigSeverity.Warning, 'always', 'foo']])
+		getForcedCaseFn(['name', [RuleConfigSeverity.Warning, 'always', 'foo']])('')
 	).toThrow('Unknown target case "foo"');
 });
 
@@ -88,13 +88,14 @@ test('should convert text correctly', () => {
 		'name',
 		[RuleConfigSeverity.Warning, 'always', 'sentence-case'],
 	]);
-	expect(rule('TEST_FOOBar-baz baz')).toBe('Test_foobar-baz baz');
+	expect(rule('TEST_FOOBar-baz baz')).toBe('TEST_FOOBar-baz baz');
+	expect(rule('some test')).toBe('Some test');
 
 	rule = getForcedCaseFn([
 		'name',
 		[RuleConfigSeverity.Warning, 'always', 'sentencecase'],
 	]);
-	expect(rule('TEST_FOOBar-baz baz')).toBe('Test_foobar-baz baz');
+	expect(rule('TEST_FOOBar-baz baz')).toBe('TEST_FOOBar-baz baz');
 
 	rule = getForcedCaseFn([
 		'name',