RDKB-64347: Fixing coverity issues

[bharathivelp]

Reason for change: Fixing Low priority Coverity issues.
Test Procedure: Build should be successful and the regression test should also succeed.
 
Risks: Low
Priority: P1
Signed-off-by: Velpula_Bharathi@comcast.com

[Copilot]

Pull request overview

This PR addresses low-priority Coverity findings by replacing potentially unsafe string copies, removing unused variables/logic, and eliminating a dead store after free().

Changes:

• Replaced a strcpy() with a bounded snprintf() when setting the default Passpoint HESSID.
• Removed an unused ret variable and simplified HAL apply analytics status reporting on the success path.
• Removed a dead assignment (buff = NULL) immediately after free(buff).

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
source/core/wifi_passpoint.c	Uses bounded formatting to avoid potential buffer overflow when setting default HESSID.
source/core/wifi_ctrl_webconfig.c	Cleans up unused variable and simplifies success status string construction for analytics.
source/apps/blaster/wifi_single_client_msmt.c	Removes dead store after free() to satisfy static analysis.

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