Deprecate span-v2-incompatible properties on `StartSpanOptions`

[Lms24]

For spans v2, we'll remove a couple of options from StartSpanOptions that should no longer be surfaced to users:

• op - to be replaced by setting the sentry.op attribute
  • I think this is technically optional, but we want to de-emphasize op as something users should worry about. For us intern, it means we convert places where we set op to use the attribute instead.
• forceTransaction - to be removed
  • We want to remove this use case. If popular demand requires it, there are workarounds like using startNewTrace and continueTrace callbacks, in combination with the parentSpan option.
• experimental.standalone - to be replaced by sending v2 spans
  • This was only used by web vitals

[linear-code]

JS-2157