Refactor & fix undesired exceptions in AS Jobs

[puntope]

Changes proposed in this Pull Request:

Closes part of #2617

• This PR adds some try catch preventing AS to fail when saving the GTIN
• Additionally this PR refactors some of the common methods to make the code cleaner

Screenshots:

Detailed test instructions:

1. Run the GTIN migration with the next GTINs
2. GTINs with dashes but 8 numbers
3. GTINs with other chars like dots . or letters
4. GTIN that also has the GTIN saved in Product Inventory for that product
5. Duplicated GTIN
6. GTINS in variations
7. See the AS doesn't fail and you can see some logs also.

Additional details:

Changelog entry

Fix - Prevent fatal in GTIN MIgration AS Job

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 38 lines in your changes missing coverage. Please review.

Project coverage is 64.9%. Comparing base (8b7c586) to head (734a77a).
Report is 14 commits behind head on add/support-core-gtin-field.

Files with missing lines	Patch %	Lines
src/Jobs/MigrateGTIN.php	0.0%	16 Missing ⚠️
src/HelperTraits/GTINMigrationUtilities.php	0.0%	12 Missing ⚠️
src/Utility/WPCLIMigrationGTIN.php	0.0%	10 Missing ⚠️

Additional details and impacted files

@@                       Coverage Diff                       @@
##             add/support-core-gtin-field   #2666     +/-   ##
===============================================================
+ Coverage                           64.7%   64.9%   +0.2%     
- Complexity                          4638    4667     +29     
===============================================================
  Files                                798     478    -320     
  Lines                              24536   19517   -5019     
  Branches                            1242       0   -1242     
===============================================================
- Hits                               15875   12674   -3201     
+ Misses                              8488    6843   -1645     
+ Partials                             173       0    -173     

Flag	Coverage Δ
js-unit-tests	?
php-unit-tests	64.9% <0.0%> (-0.4%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
src/Utility/WPCLIMigrationGTIN.php	0.0% <0.0%> (ø)
src/HelperTraits/GTINMigrationUtilities.php	29.6% <0.0%> (-23.7%)	⬇️
src/Jobs/MigrateGTIN.php	0.0% <0.0%> (ø)

... and 322 files with indirect coverage changes

[mikkamp]

Thanks for the changes, they are looking good. I just left a few minor nitpicks but the migration is working. I can confirm that I see log messages, including an error logged for a duplicate GTIN:

[mikkamp]

Not a big deal, and we don't seem to be consistent. But in most cases in the code we add use WC_Product to be able to remove the \. But I'm not attached to either method so both are fine.

[mikkamp]

Just a small nitpick about the wording (this should be plural):

Suggested change

	* Add --debug to see this kind of logs in WP CLI
	* Add --debug to see these logs in WP CLI