Enhancement: [prefer-optional-chain] Support simple equals expressions

[boris-petrov]

Before You File a Proposal Please Confirm You Have Done The Following...

• I have searched for related issues and found none that match my proposal.
• I have searched the current rule list and found no rules that match my proposal.
• I have read the FAQ and my problem is not listed.

My proposal is suitable for this project

• I believe my proposal would be useful to the broader TypeScript community (meaning it is not a niche proposal).

Link to the rule's documentation

https://typescript-eslint.io/rules/prefer-optional-chain/

Description

prefer-optional-chain could also support cases like the following:

if (this.foo != null && this.foo.bar === 1) {
}

This is probably a very common pattern and would be nice to be handled by the rule.

Fail

if (this.foo != null && this.foo.bar === 1) {
}

Pass

if (this.foo?.bar === 1) {
}

Additional Info

No response

[bradzacher]

This would be covered by #7170