Markdown image with no title is not parsed

[andydotxyz]

Checklist

• I have searched the issue tracker for open issues that relate to the same problem, before opening a new one.
• This issue only relates to a single bug. I will open new issues for any other problems.

Describe the bug

If the title field is blank in my markdown the image is not added.

How to reproduce

Run test TestRichTextMarkdown_Image with "title" removed from the input string.

Screenshots

No response

Example code

	r := NewRichTextFromMarkdown("![](../../theme/icons/fyne.png)")

	assert.Equal(t, 1, len(r.Segments))
	if img, ok := r.Segments[0].(*ImageSegment); ok {
		assert.Equal(t, storage.NewFileURI("../../theme/icons/fyne.png"), img.Source)
	} else {
		t.Error("Segment should be a Image")
	}

Fyne version

v2.3.0

Go compiler version

1.18.4

Operating system

macOS

Operating system version

Monterey

Additional Information

No response

[andydotxyz]

Fixed on develop