chore(karma-credential-loader): remove declaration as false from tsconfig

declarationDir can't be defined with declaration as false

Author: trivikr

packages/karma-credential-loader/tsconfig.cjs.json

@@ -1,6 +1,5 @@
 {
   "compilerOptions": {
-    "declaration": false,
     "strict": false,
     "declarationDir": "./types",
     "rootDir": "./src",

packages/karma-credential-loader/tsconfig.es.json

@@ -1,6 +1,5 @@
 {
   "compilerOptions": {
-    "declaration": false,
     "strict": false,
     "lib": ["es2015"],
     "declarationDir": "./types",