Validation Regexp fails if title has "." in the text

Problem/Motivation

Validation Regexp fails if title has "." in the text

Steps to reproduce

If validation is working (see issue https://www.drupal.org/project/media_entity_flickr/issues/3216437), and you try to create a Flicker entity from a Flickr photo that has a "." in the title, it will be rejected as invalid. eg:

<a data-flickr-embed="true" href="https://www.flickr.com/photos/hoting2000/42633796482/" title="c. 1927 Over Kaitak airport"><img src="https://live.staticflickr.com/1735/42633796482_96ea80492a_o.jpg" width="1245" height="770" alt="c. 1927 Over Kaitak airport"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>

Proposed resolution

The problem is in the $validationRegexp strings in Flickr.php. To fix it, change the title section of both strings from:

title=\"(?P<title>[^.*]+)\"

to:

title=\"(?P<title>[^\"]+)\"

Remaining tasks

User interface changes

API changes

Data model changes