Fix newsletter subscription cleanup on customer update

[Codencode]

Questions	Answers
Description?	This PR fixes #135 by preserving existing emailsubscription records when a customer account is updated without changing the newsletter subscription status. The customer is reloaded from the database to retrieve the newsletter state before the update, while the object received by the hook already contains the new value. Comparing both states allows the module to detect an actual newsletter subscription transition (0 -> 1) and remove the existing emailsubscription record only in that case. I also added comments in both hookActionObjectCustomerUpdateBefore() and hookActionCustomerAccountUpdate() to clarify this behavior and make the relationship between the persisted newsletter state and the new customer state easier to understand.
Type?	bug fix
BC breaks?	no
Deprecations?	no
Fixed ticket?	Fixes #135
How to test?	1. Subscribe to the newsletter as a guest. 2. Create a customer account using the same email address without selecting the newsletter option. 3. Verify that the corresponding emailsubscription record is still present. 4. Update an unrelated customer field, such as the first name. 5. Verify that the emailsubscription record is preserved. 6. Enable the newsletter option from the customer account. 7. Verify that the emailsubscription record is removed and the customer newsletter status is enabled.

[Touxten]

It's ok for me see video :

test-email.mp4

[devmysz]

Thank you @Codencode for your PR.

QA ✅

Tested successfully.

Covered scenarios:

Existing newsletter subscriber → checkout as guest without newsletter consent:
emailsubscription preserved
customer.newsletter = 0
Guest/customer profile updated without changing newsletter consent:
emailsubscription preserved
customer.newsletter = 0
Guest converted to registered customer without newsletter consent:
emailsubscription preserved
customer.newsletter = 0
Customer account created during checkout without newsletter consent:
emailsubscription preserved
customer.newsletter = 0
Newsletter consent enabled later, both for guest during checkout and for registered customer:
emailsubscription entry removed
customer.newsletter = 1

[Touxten]

@devmysz I'm waiting for this PR, and then I'll release a new version of the module

[Codencode]

@devmysz I'm waiting for this PR, and then I'll release a new version of the module

@Touxten, can we wait to resolve this issue: #121 (comment) before releasing the new version?

Keep in mind that if a new PR needs to be created or #121 needs to be modified, I'll do it right away.

[Touxten]

Yes i wait Kristian comment