Release agent version 1.300048.1b904

[jefchien]

Description of changes

Update all samples to use the latest agent image version 1.300048.1b904. See https://github.com/aws/amazon-cloudwatch-agent/releases/tag/v1.300048.1 for changes.

License

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Requirements

Before committing the code, please verify the following:

• If this commit includes changes to existing sample configurations, you acknowledge that you have confirmed this will not impact existing customer behavior.
• If not necessary, consider creating a new sample configuration for this change.