i.eb.hsebal01: fix manual pixel handling

[jayneel-shah18]

This PR fixes issues mentioned in #6003 that prevent the module from working properly when manual wet/dry pixels are specified:

• Missing initialization of raster arrays:
  • In manual mode, d_t0dem, d_z0m, and d_eact arrays were never populated before iteration loops. This caused all pixel values to remain zero, leading to invalid d_rah_dry and d_roh_dry, NaN results, and premature failure with Delta T Convergence failed.
  • Fix: Added this loop after raster input buffers are allocated:

/* Always read t0dem, z0m, and eact into the arrays */
for (row = 0; row < nrows; row++) {
    Rast_get_d_row(infd_t0dem, inrast_t0dem, row);
    Rast_get_d_row(infd_z0m, inrast_z0m, row);
    Rast_get_d_row(infd_eact, inrast_eact, row);

    for (col = 0; col < ncols; col++) {
        d_t0dem[row][col] = ((DCELL *)inrast_t0dem)[col];
        d_z0m[row][col] = ((DCELL *)inrast_z0m)[col];
        d_eact[row][col] = ((DCELL *)inrast_eact)[col];
    }
}

• Row/column assignment for manual coordinates:
  • When using manual mode without the -c flag, the provided wet/dry pixel coordinates must be interpreted as row/col indices. These were not assigned properly to rowWet, colWet, rowDry, colDry, leading to uninitialized or stale values.
  • Fix: Added this logic:

/* If -c flag is not set, interpret inputs as integer row/col indices */
if (!flag3->answer) {
    rowWet = (int)m_row_wet;
    colWet = (int)m_col_wet;
    rowDry = (int)m_row_dry;
    colDry = (int)m_col_dry;
}

• Verbosity cleanup:
  • The verbosity messages for projection coordinates were displayed regardless of whether -c was specified, causing confusion.
  • Fix: Indented the messages so they only print if flag3->answer is true:

/* If pixels locations are in projected coordinates */
if (flag3->answer) {
    G_verbose_message(_("Manual wet/dry pixels in image coordinates"));
    G_verbose_message(_("Wet Pixel=> x:%f y:%f"), m_col_wet, m_row_wet);
    G_verbose_message(_("Dry Pixel=> x:%f y:%f"), m_col_dry, m_row_dry);
}

The changes in the module have been verified to run successfully in all modes:

• Automatic pixel selection (-a)
• Manual row/col pixel input (without -c)
• Manual projected coordinates (with -c)

The results matched the expected output rasters in each mode.

A test suite for the module will be added once these changes are merged.

Closes #6003