Upgrade eslint-plugin-matrix-org to 1.2.1

This upgrade came with a number of new lints that needed to be fixed across the code base. Primarily: explicit return types on functions, and explicit visibility modifiers on class members.

src/UrlParams.ts

@@ -134,7 +134,7 @@ class ParamParser {
   private fragmentParams: URLSearchParams;
   private queryParams: URLSearchParams;
 
-  constructor(search: string, hash: string) {
+  public constructor(search: string, hash: string) {
     this.queryParams = new URLSearchParams(search);
 
     const fragmentQueryStart = hash.indexOf("?");
@@ -146,18 +146,18 @@ class ParamParser {
   // Normally, URL params should be encoded in the fragment so as to avoid
   // leaking them to the server. However, we also check the normal query
   // string for backwards compatibility with versions that only used that.
-  getParam(name: string): string | null {
+  public getParam(name: string): string | null {
     return this.fragmentParams.get(name) ?? this.queryParams.get(name);
   }
 
-  getAllParams(name: string): string[] {
+  public getAllParams(name: string): string[] {
     return [
       ...this.fragmentParams.getAll(name),
       ...this.queryParams.getAll(name),
     ];
   }
 
-  getFlagParam(name: string, defaultValue = false): boolean {
+  public getFlagParam(name: string, defaultValue = false): boolean {
     const param = this.getParam(name);
     return param === null ? defaultValue : param !== "false";
   }