Revert Java to 18 on CircleCI for 1.10.x and above

[jonatan-ivanov]

Because of #3549 we can't update to Gradle 7.6 on every branch, this is the Gradle version situation right now:

• 1.9.x -> Gradle 7.6
• 1.10.x -> Gradle 7.5.1
• main -> Gradle 7.5.1

Gradle 7.5.1 does not support Java 19 so we need to keep 1.10.x and main on Java 18.
Java 19 was introduced in #3550

[jonatan-ivanov]

/cc @izeye: I needed to partially revert your changes to make the build green, once we upgrade to Gradle 7.6.1, we can upgrade to Java 19 too.