Update OpenTelemetry span and attribute names

[alexmojaki]

Some changes we need to be more in line with the OTel specs:

Agent runs:

• Span name should be invoke_agent {gen_ai.agent.name} instead of agent run
• Attribute agent_name should be gen_ai.agent.name. For this one, let's just duplicate the attribute immediately, i.e. set both names to the same value.

Tool execution:

• Span name should be execute_tool {gen_ai.tool.name} instead of running tool
• gen_ai.tool.call.arguments where we’ve been using tool_arguments
• gen_ai.tool.call.result where we’ve been using tool_response

All these names are already being actively used in queries, changing them would cause breakages, although just copying agent_name is fine. Most users probably don't actually care about these right now. So I think InstrumentationSettings(version=3) should be introduced to allow enabling some or all of these changes, while the default version=2 remains. If making all these changes in a single PR is a pain, then version=3 can apply some subset while the rest is for version=4 or beyond.

The span names are the most important for the sake of improving the display in #2925.

The gen_ai.tool.call.* attributes are not even part of the released spec yet, so not very important.

[VSD10]

Hey hi, can i work on this issue?? I hope i can resolve this

[bitnahian]

Hi. Is this still being worked on? Otherwise I'd be happy to take it.

[alexmojaki]

@VSD10 opened #2967, not sure if they still plan on working on it.

[alexmojaki]

Reopening because at the very least we should document the new version.