`bs4DashBrand` visual bug when using fixed navbar and disabled sidebar

[lanceupton]

I'm a huge fan of this package and typically default to this framework when designing applications.

I ran into a display issue, described below.

Details of Issue

To reproduce:

1. Use bs4DashNavbar(fixed = TRUE, ...)
2. Use bs4DashSidebar(disable = TRUE)

Observed: The bs4DashBrand component visually overlaps components in the navbar.

Reprex

library(shiny)
library(bs4Dash)

header <- bs4DashNavbar(
  title = bs4DashBrand(
    title = "Application Title",
    image = "https://picsum.photos/40/40",
  ),
  fixed = TRUE,
  leftUi = dropdownMenu(
    type = "notifications",
    notificationItem(
      text = "test"
    )
  )
)

# WITH SIDEBAR - THIS WORKS AS INTENDED
shinyApp(
  ui = bs4DashPage(
    header = header,
    sidebar = bs4DashSidebar(
      bs4SidebarMenu(
        bs4SidebarMenuItem("Tab 1"),
        bs4SidebarMenuItem("Tab 2")
      )
    ),
    body = bs4DashBody()
  ),
  server = function(input, output, session) {},
  options = list(launch.browser = TRUE)
)

# DISABLED SIDEBAR - BRAND COMPONENT VISUAL BUG
shinyApp(
  ui = bs4DashPage(
    header = header,
    sidebar = bs4DashSidebar(disable = TRUE),
    body = bs4DashBody()
  ),
  server = function(input, output, session) {},
  options = list(launch.browser = TRUE)
)

Screenshot of visual issue:

Session info:

R version 4.1.2 (2021-11-01)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 10 x64 (build 19044)

Matrix products: default

locale:
[1] LC_COLLATE=English_United States.1252  LC_CTYPE=English_United States.1252   
[3] LC_MONETARY=English_United States.1252 LC_NUMERIC=C                          
[5] LC_TIME=English_United States.1252    

attached base packages:
[1] stats     graphics  grDevices datasets  utils     methods   base     

other attached packages:
[1] bs4Dash_2.1.0 shiny_1.7.2  

loaded via a namespace (and not attached):
 [1] Rcpp_1.0.9        digest_0.6.29     later_1.3.0       mime_0.12         R6_2.5.1          xtable_1.8-4     
 [7] lifecycle_1.0.2   jsonlite_1.8.0    magrittr_2.0.3    cachem_1.0.6      rlang_1.0.5       cli_3.4.0        
[13] renv_0.15.5       fontawesome_0.3.0 rstudioapi_0.14   promises_1.2.0.1  jquerylib_0.1.4   bslib_0.4.0      
[19] ellipsis_0.3.2    tools_4.1.2       httpuv_1.6.6      fastmap_1.1.0     compiler_4.1.2    memoise_2.0.1    
[25] htmltools_0.5.3   sass_0.4.2