[Bugfix] fix check kv cache memory log info

[BoL0150]

The estimated_msg variable was not correctly concatenated and assigned, resulting in incomplete error messages. This issue occurred in the following code block:

if estimated_max_len > 0:
    estimated_msg = " Based on the available memory,"
    f" the estimated maximum model length is {estimated_max_len}."

I merged the string concatenation into a single line to ensure the estimated_msg variable is correctly assigned the concatenated message. The updated code is as follows:

if estimated_max_len > 0:
    estimated_msg = " Based on the available memory," \
                    f" the estimated maximum model length is {estimated_max_len}."

No other functionality is impacted by this change.

[github-actions]

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