Show device name and error in Shelly BLE provisioning failure messages

[bdraco]

Proposed change

Improve error messages shown in the UI when BLE WiFi provisioning fails. Previously, error messages were generic and didn't include the device name or actual error that occurred.

WiFi scan failure

Before:

Failed to scan for WiFi networks via Bluetooth. The device may be out of range or Bluetooth connection failed. Would you like to try again?

After:

Failed to scan for WiFi networks on ShellyPlus2PM-C049EF8873E8 via Bluetooth: DeviceConnectionError(TimeoutError()). The device may be out of range or Bluetooth connection failed. Would you like to try again?

Provisioning failure

Before:

The device did not connect to MyNetwork. This may be due to an incorrect password or the network being out of range. Would you like to try again?

After:

ShellyPlus2PM-C049EF8873E8 did not connect to MyNetwork: DeviceConnectionError('BLE connection lost'). This may be due to an incorrect password or the network being out of range. Would you like to try again?

This helps users identify which device failed and provides the actual error for troubleshooting.

Type of change

• Bugfix (non-breaking change which fixes an issue)

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue:
• Link to documentation pull request:
• Link to developer documentation pull request:
• Link to frontend pull request:

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[home-assistant]

Hey there @bieniu, @thecode, @chemelli74, mind taking a look at this pull request as it has been labeled with an integration (shelly) you are listed as a code owner for? Thanks!

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