feat: Merge additional tags into vpc_endpoint

[mitch-hamm]

(If this PR fixes a github issue, please add Fixes #<xyz>.)

Fixes #

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Motivation

When passing additional_tags to the module, it should also be applied to this resource if created

Modifications

Update the passed tags to include merging the additional_tags into the pre-defined StreamNative tags

Verifying this change

• Make sure that the change passes the CI checks.

(Please pick either of the following options)

This change is a trivial rework / code cleanup without any test coverage.

(or)

This change is already covered by existing tests, such as (please describe tests).

(or)

This change added tests and can be verified as follows:

(example:)

• Added integration tests for end-to-end deployment with large payloads (10MB)
• Extended integration test for recovery after broker failure

Documentation

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Need to update docs?

• doc-required

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• no-need-doc

  No need to update docs. This just updates passing the additional tags to a missing resource

• doc

  (If this PR contains doc changes)

[github-actions]

@mitch-hamm:Thanks for your contribution. For this PR, do we need to update docs?
(The PR template contains info about doc, which helps others know more about the changes. Can you provide doc-related info in this and future PR descriptions? Thanks)

[github-actions]

@mitch-hamm:Thanks for providing doc info!