Bump TypeDB Client Java to 2.18

[jamesreprise]

What is the goal of this PR?

We've bumped the java client that Studio uses to 2.18.

What are the changes implemented in this PR?

We've

• replaced uses of var with cVar.
• made use of the set of annotations rather than a single boolean for key.
• removed a check isKeyable that determines whether an attribute can be used as a key.
• bumped the versions of client-java, common and typedb to 2.18.0.

[typedb-bot]

PR Review Checklist

Do not edit the content of this comment. The PR reviewer should simply update this comment by ticking each review item below, as they get completed.

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Trivial Change

• [x] This change is trivial and does not require a code or architecture review.

Code

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Architecture

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