Add details when error loading package

[dentra]

What does this implement/fix?

This PR will add additional information if the package loading fails.

before:

Failed to load packages. yeelight_light_ceil26.yaml is not a valid YAML file. Please check the file contents.

after:

Failed to load packages. yeelight_light_ceil26.yaml is not a valid YAML file. Please check the file contents.
Error reading file config/.esphome/packages/155aacf3/secrets.yaml: [Errno 2] No such file or directory: 'config/.esphome/packages/155aacf3/secrets.yaml'

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Other

Related issue or feature (if applicable): fixes

Pull request in esphome-docs with documentation (if applicable): esphome/esphome-docs#

Test Environment

• ESP32
• ESP32 IDF
• ESP8266
• RP2040
• BK72xx
• RTL87xx

Example entry for config.yaml:

packages:
  ceil26: github://syssi/esphome-yeelight-ceiling-light/yeelight_light_ceil26.yaml

Checklist:

• The code change is tested and works locally.
• Tests have been added to verify that the new code works (under tests/ folder).

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated in esphome-docs.