[api-minor] Let the cMapPacked parameter, in getDocument, default to true

The initial CMap support was added in PR 4259 using the "raw" Adobe files, however they were quickly deemed to be unnecessarily large. As a result PR 4470 introduced the more compact "binary" CMap format, with both of those PRs being included in the very same release (version `0.8.1334`) .

Please note that we've thus never shipped anything *except* the "binary" CMap files with the PDF library, and furthermore note that we've not even once updated the CMap files since they were originally added almost nine years ago.

Requiring users to remember that `cMapPacked = true` is necessary, in addition to setting the `cMapUrl` parameter, in order for CMap loading to work feels like a less than ideal API.
Hence this patch, which suggests that we simply let `cMapPacked` default to `true` now.

src/display/api.js

@@ -166,7 +166,7 @@ if (typeof PDFJSDev === "undefined" || !PDFJSDev.test("PRODUCTION")) {
  * @property {string} [cMapUrl] - The URL where the predefined Adobe CMaps are
  *   located. Include the trailing slash.
  * @property {boolean} [cMapPacked] - Specifies if the Adobe CMaps are binary
- *   packed or not.
+ *   packed or not. The default value is `true`.
  * @property {Object} [CMapReaderFactory] - The factory that will be used when
  *   reading built-in CMap files. Providing a custom factory is useful for
  *   environments without Fetch API or `XMLHttpRequest` support, such as
@@ -347,6 +347,7 @@ function getDocument(src) {
     params[key] = val;
   }
 
+  params.cMapPacked = params.cMapPacked !== false;
   params.CMapReaderFactory =
     params.CMapReaderFactory || DefaultCMapReaderFactory;
   params.StandardFontDataFactory =

src/display/base_factory.js

@@ -65,7 +65,7 @@ class BaseCanvasFactory {
 }
 
 class BaseCMapReaderFactory {
-  constructor({ baseUrl = null, isCompressed = false }) {
+  constructor({ baseUrl = null, isCompressed = true }) {
     if (this.constructor === BaseCMapReaderFactory) {
       unreachable("Cannot initialize BaseCMapReaderFactory.");
     }