Fix #21406: Hide repo information from file view/blame mode (#21420)

# Summary

The repo information such as description, stats and topics are getting
displayed in the top-bar when viewing a file. This has been fixed to
display the repo information only while navigating the repo and not
while viewing or blaming a file from the repo

## Before fix

Screenshot from the issue


![image](https://user-images.githubusercontent.com/47709856/195278543-9afbb735-7bd3-4f42-b3ba-da514c6989d2.png)

## After the fix

- **Repo homepage**

The repo description, topics and summary will be displayed


![image](https://user-images.githubusercontent.com/47709856/195443913-2ca967cd-6694-4a97-98d0-4d0750692b5d.png)

- **When opening a file**

The repo description, topic and summary has been conditionally hidden
from the view

<img width="1311" alt="image"
src="https://user-images.githubusercontent.com/47709856/195278964-9479231c-62ad-4c0e-b438-2018f22289db.png">

- **When running blame on a file**

> This was originally not part of the issue #21406. However the fix
seems relevant for the blame view as well.

<img width="1312" alt="image"
src="https://user-images.githubusercontent.com/47709856/195279619-02010775-aec3-4c8d-a184-d2d838c797e8.png">

- **From within a directory**

The repo description, topics and summary will not be displayed


![image](https://user-images.githubusercontent.com/47709856/195444080-ff5b2def-7e0f-47d7-b54a-7e9df5f9edd8.png)


Supporting integration tests have also been added.

routers/web/repo/view.go

@@ -119,6 +119,7 @@ func renderDirectory(ctx *context.Context, treeLink string) {
 	}
 
 	if ctx.Repo.TreePath != "" {
+		ctx.Data["HideRepoInfo"] = true
 		ctx.Data["Title"] = ctx.Tr("repo.file.title", ctx.Repo.Repository.Name+"/"+path.Base(ctx.Repo.TreePath), ctx.Repo.RefName)
 	}
 
@@ -360,6 +361,7 @@ func renderReadmeFile(ctx *context.Context, readmeFile *namedBlob, readmeTreelin
 
 func renderFile(ctx *context.Context, entry *git.TreeEntry, treeLink, rawLink string) {
 	ctx.Data["IsViewFile"] = true
+	ctx.Data["HideRepoInfo"] = true
 	blob := entry.Blob()
 	dataRc, err := blob.DataAsync()
 	if err != nil {