[FR] Support generateVerifyAndChangeEmailLink

**Is your feature request related to a problem? Please describe.**

I have a Spring Boot application for which I use Firebase Admin SDK installed from Maven, version 9.7.0.

As I'd like to send to my users custom email templates regarding email confirmation, password reset and others. To do that I have to use link generation methods that SDK provides and then include that link in custom templates.

I noticed, that latest version of SDK does not support generating email links for changing user e-mail address
i.e. **generateVerifyAndChangeEmailLink**, that seems to be already supported for example in Node SDK.

Supported link types in SDK as of now:
```
static enum EmailLinkType {
VERIFY_EMAIL,
EMAIL_SIGNIN,
PASSWORD_RESET;
}
```

I believe VERIFY_AND_CHANGE_EMAIL also might be useful alongside with supporting methods.

**Describe the solution you'd like**
Add support for generateVerifyAndChangeEmailLink with VERIFY_AND_CHANGE_EMAIL.

**Describe alternatives you've considered**
I believe as an alternative it might be possible to create API calls from scratch though I believe having dedicated methods is better and easier for developers.

Start by locating the Java SDK's email-link generation API and the EmailLinkType enum mentioned in the issue, then compare the existing supported link types with the Node SDK's generateVerifyAndChangeEmailLink support. Done means the Java SDK exposes VERIFY_AND_CHANGE_EMAIL and a corresponding generateVerifyAndChangeEmailLink capability, with coverage for the new behavior.

Scritto dal modello di indicizzazione a partire dal testo della issue.