Top and Bottom plots seem to have less spacing when using `subplot` in `plotly`

Description:

When attempting to display multiple histograms using subplot from the plotly package, the plots in the top row and bottom row appear with less spacing, making them difficult to analyze. This issue is primarily reproducible when there are large number of visualizations to plot together.

Here is a minimal reprex for the same:

# Load necessary libraries
library(ggplot2)
library(plotly)

# set seed for reproducibility
set.seed(123)

# simulate a dataset
simulateDataset <- function(numRows = 100, numCols = 40) {
  data <- data.frame(matrix(nrow = numRows, ncol = numCols))
  
  for (i in 1:numCols) {
    if (i %% 2 == 0) {
      data[[i]] <- rnorm(numRows, mean = 50, sd = 10)  # Normal distribution
    } else {
      data[[i]] <- rexp(numRows, rate = 0.1)           # Exponential distribution
    }
  }
  
  names(data) <- paste0("Var", 1:numCols)
  return(data)
}

# simulate the data
df <- simulateDataset(numRows = 100, numCols = 45)

# create histograms and convert to plotly
plotList <- lapply(names(df), function(colName) {
  if (is.numeric(df[[colName]])) {
    p <- ggplot(df, aes(x = .data[[colName]])) + 
      geom_histogram(binwidth = 0.5, fill = 'grey', color = 'black')
    
    ggplotly(p)
  }
})

# define number of rows based on number of plots in each row
numberOfRows <- ceiling(length(plotList) / 3)

# display all plots together using subplot
subplot(plotList, nrows = numberOfRows, margin = 0.05, titleX = TRUE, titleY = TRUE)

Expected Behavior:
Each histogram should have equal margins, with appropriate spacing and labels visible.

Screenshots

Commencez par exécuter le reprex R fourni avec subplot et 45 histogrammes afin de reproduire le problème d’espacement entre les lignes supérieure et inférieure. Suivez le comportement de mise en page de subplot et vérifiez que les histogrammes obtenus ont des marges égales avec des libellés visibles ; le problème est résolu lorsque les graphiques supérieur et inférieur sont espacés de manière cohérente.