Validate links during span creation

[emdneto]

Describe your environment

OS: Ubuntu Python version: 3.12 SDK version: 1.25.0 API version: 1.25.0

What happened?

We are recording invalid links when adding links during span creation.

Steps to Reproduce

 from opentelemetry import trace
from opentelemetry.sdk.trace import TracerProvider
from opentelemetry.sdk.trace.export import (
    SimpleSpanProcessor,
    ConsoleSpanExporter,
)

trace.set_tracer_provider(TracerProvider())
trace.get_tracer_provider().add_span_processor(SimpleSpanProcessor(ConsoleSpanExporter()))

tracer = trace.get_tracer("my.tracer")
with tracer.start_as_current_span("root", links=[trace.Link(trace.INVALID_SPAN_CONTEXT)]) as root:
    pass

Expected Result

"links": []

Since this is the preferred method to add links, I suppose we should also validate links at span creation

Actual Result

    "links": [
        {
            "context": {
                "trace_id": "0x00000000000000000000000000000000",
                "span_id": "0x0000000000000000",
                "trace_state": "[]"
            },
            "attributes": {}
        }
    ],

Additional context

No response

Would you like to implement a fix?

Yes

[UjjwalSaini07]

Great Change