Allow suppressImplicitAnyIndexErrors config in TS

The suppressImplicitAnyIndexErrors config is deprecated in Typescript
5.0 and above, and will be removed in Typescript 5.5. For now, we can
still use it by setting "ignoreDeprecations": "5.0", but we'll need to
go through our JS code and switch to individual @ts-ignore lines at
every occurrence of implicit "any" before we can update to TS 5.5.

tsconfig.json

@@ -14,6 +14,7 @@
     "downlevelIteration": true,
     "emitDecoratorMetadata": true,
     "experimentalDecorators": true,
+    "ignoreDeprecations": "5.0",
     "importHelpers": true,
     "lib": ["es7", "dom"],
     "module": "es6",