chore: downgrade OpenTelemetry to v1.32.0 and remove auto/sdk

[NekoHK]

Changes

• Downgrade OpenTelemetry to v1.32.0
• Remove auto/sdk usage

[hase1128]

@mgazz
To avoid using the LGPL license, we would like to use otel/sdk instead of auto/sdk. (More precisely, libbpf, which auto/sdk uses, contains code licensed under the LGPL.)

Our investigation revealed the following:
・Since auto/sdk is included as an indirect dependency of otel/sdk, it will be automatically added whenever we run go mod tidy as long as otel/sdk remains in the project.
・Consequently, even if we remove it once, it will be added again.

As a temporary workaround to avoid this, we downgraded the otel/sdk version from 1.33.0 to 1.32.0. Since auto/sdk has no dependencies on version 1.32.0, we can remove it.

We will need to consider how to handle tracing in the future, but I believe this is sufficient as a temporary measure for now.