File Handling: Fails from most apps due to read-only permission

**Describe the bug**
When opening a file from most apps, into my TWA, it fails with the following error message: `Failed to open a file - no read / write permissions: ...`. From my testing, it seems to happen because most apps send the files as read-only, instead of read *and* write.

**To Reproduce**
Steps to reproduce the behavior:
1. Install a demo TWA that registers a file handler, for any file format of your choosing
2. Open "Files by Google", tap on the 3 dots on a file (in the same file format as step 1) > Open with > demo TWA
3. The TWA launches, but without receiving the file
4. See error in Logcat: `Failed to open a file - no read / write permissions: ...`

**Expected behavior**
The file should be received, even if it's read-only.

For example, Chrome's File Handling API on Windows allows opening read-only files too.

How Chrome seems to behave with read-only files on Windows

In JS, on the `launchParams`'s `FileSystemFileHandle` I can call `getFile()` to read the file without any issues.

However, calling `FileSystemFileHandle.createWritable()` throws an error: `NoModificationAllowedError: Failed to execute 'createWritable' on 'FileSystemFileHandle': Cannot write to a read-only file.`

**Code Snippets**
It seems to be caused by this check: https://github.com/GoogleChrome/android-browser-helper/blob/ba8eb4d4aa9df52828a5050ce585434e1587d3d3/androidbrowserhelper/src/main/java/com/google/androidbrowserhelper/trusted/LauncherActivity.java#L318-L323

@orbital17 Could you please change it, so that it only checks for `Intent.FLAG_GRANT_READ_URI_PERMISSION`?

**Additional context**
For comparison, when using the classic built-in Files app (`com.google.android.documentsui`) to do Open with > demo TWA, the file is received successfully, because it's sent with read and write permission.