Fix side-effect of default options in Beam Operators

[potiuk]

Some of the operators in Apache Beam had side effect that they modified detault options passed to it in constructor, and in case of xdist tests it had side effect that they could impact other test results (this happened recently in main). The default options are already set by the Dataflow mixin in execute method in all Beam operators, but in Python and Go operator the defaults are also set in the constructor.

Setting the defaults in mixin uses deepcopy to avoid such side effects.

This might be intended, so this PR rather than removing default settings in the constructor, also adds deepcopy in them and fixes resulting tests - removing the defaults in tests that do not have the defaults set in the constructor.

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[potiuk]

So - ideally - we could likely remove if we are sure it's fine, but even if we could, it should be a separate PR IMHO.

        self.pipeline_options.setdefault("labels", {}).update(
            {"airflow-version": "v" + version.replace(".", "-").replace("+", "-")}
        )

[Taragolis]

Yeah, all logic around templated_fields should be moved into the execute method in any way, otherwise it will only work in some simple cases.